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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Protecting images from theft

You want people to visit your website, see your wonderful product and be sold on what you have to offer through wonderful pictures. But you don't want them to take copies of the pictures and use them on their own web sites, nor do you want them to link in to your images and use your costly artwork and bandwidth for their own purposes. Right? It's a bit of a conundrum, isn't it?

The graphics on our website aren't our bread-and-butter living, so I don't mind the odd image being copied or even people using a selection of images - but what if my images were my livelihood? Here are some of the techniques I would look at:

a) Marking the images in some way - either a logo in one corner, or a watermark across the picture. On colour mapped formats, the water mark could be in "white on white" so that it wouldn't be visible to the naked eye, but could be seen via certain software. Some images formats also allow for annotation in their headers.

b) Supplying the online images only at a lower resolution as needed by the web page. This will cut down on theft for print, but the resolution might not be a problem for a web site thief. PHP includes a thumbnailing capability - sample code - which means you can store high resolution on the server but only provide low res on the fly.

c) Image splitting, where images are held in multiple images. Try to copy the whole image below onto your web site - you won't find it as easy as usual ;-) :



Once again, PHP can help you with the setup.

The techniques I have listed above all effect what's sent to the client when the graphics are being displayed, but there are some other server based techniques you could use if you've got a setup where you can front your images with PHP. Indeed, it can be much more efficient too for you to store large numbers of images in a MySQL database (or other database) rather than in a file-and-folder structure where the operating system efficiency isn't brilliant with tens of thousands of files!

d) Track and log image requests in your PHP by incoming IP address, and once a certain IP address has requested more then 20 images in a five minute period (say), start adding watermarks to the pictures through the PHP.

e) Check the referer field, and only supply unwatermarked images where the referer is a know page on your own site.

You need to code these facilities carefully bearing in mind that you may WANT spiders like Google images to grab all your pictures, and you won't want to piss off your very interested genuine customers who call up a lot of pages in their excitement with your site. Also remember that people can go to the trouble of falsifying headers if they want. You may come up with a scheme that logs image requests, and simple emails you the first time there's an unusual referer from another site, allowing you to put in a "watermark" or even "this image is stolen" response when the same remote image request comes up again.
(written 2006-05-12, updated 2006-06-05)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
W512 - Web and Intranet - Site Design Aspects
  [229] A fortunate accident - (2005-02-27)
  [261] Putting a form online - (2005-03-29)
  [288] Colour blindness for web developers - (2005-04-22)
  [319] Accommodation and landing pages - (2005-05-21)
  [345] Spotting a denial of service attack - (2005-06-12)
  [352] Improved mining techniques! - (2005-06-19)
  [391] One mans pleasure is another mans poison - (2005-07-26)
  [510] Dynamic Web presence - next generation web site - (2005-11-29)
  [556] Colour doesn't have to mean colourful - (2006-01-06)
  [649] Denial of Service ''attack'' - (2006-03-17)
  [795] Remember a site's non-technical issues too - (2006-07-07)
  [823] An excellent use for a visitor count? - (2006-08-05)
  [859] Put the answer in context - it may be printed - (2006-09-08)
  [918] Databases needn't be frightening, hard or expensive - (2006-11-08)
  [1015] Search engine placement - long term strategy and success - (2006-12-30)
  [1047] Maintainable code - some positive advice - (2007-01-21)
  [1054] UK legal requirements for your commercial web site - (2007-01-27)
  [1353] Mood shots - (2007-09-16)
  [1598] Every link has two ends - fixing 404s at the recipient - (2008-04-02)
  [2214] Global Index to help you find resources - (2009-06-01)
  [3517] Tags used in writing this blog - (2011-11-12)
  [3563] How big is a web page these days? Does the size of your pages matter? - (2011-12-26)
  [3589] Promoting a single one of your domains on the search engines - (2012-01-22)

G902 - Well House Consultants - Web site techniques, utility and visibility
  [23] Skills and responsibilities - (2004-08-22)
  [32] Web design platoon - (2004-08-29)
  [98] No more 'Error 404' pages. Something better. - (2004-10-24)
  [109] URLs - a service and not a hurdle - (2004-11-04)
  [117] A case of case - (2004-11-14)
  [142] Colour for access - (2004-12-06)
  [165] Implementing an effective site search engine - (2005-01-01)
  [173] Data Mining - (2005-01-09)
  [179] The hunt for unique words - (2005-01-16)
  [182] Your personal Google ranking - (2005-01-19)
  [197] Allow for peak traffic on your web site - (2005-02-01)
  [202] Searching for numbers - (2005-02-04)
  [222] Who are all these visitors? - (2005-02-20)
  [259] Responding to spam - (2005-03-27)
  [268] Information request forms, cleaning up spam - (2005-04-05)
  [274] Our most popular resources - (2005-04-10)
  [276] An apology to Mr Boneparte - (2005-04-11)
  [278] Cover all the options - (2005-04-13)
  [284] The Iconish language - (2005-04-19)
  [311] Growth pains - (2005-05-14)
  [314] What language is this written in? - (2005-05-17)
  [320] Ordnance Survey - using a 'Get a map' - (2005-05-22)
  [322] More maps - (2005-05-23)
  [347] Frightening and from-friend viruses and spams - (2005-06-14)
  [348] Graveyard pages - (2005-06-15)
  [369] CMS - the minefield of Choices - (2005-07-05)
  [376] What brings people to my web site? - (2005-07-13)
  [414] Form Madness - (2005-08-14)
  [492] New Navigation Aid - Launch of My Wellho - (2005-11-11)
  [528] Getting favicon to work - avoiding common pitfalls - (2005-12-14)
  [533] Bigger Box Campaign - (2005-12-18)
  [658] Keeping the visitors happy and browsing - (2006-03-26)
  [681] Mirroring a dynamic site - (2006-04-12)
  [732] Where is a web site visitor browsing from - (2006-05-24)
  [757] Horse and Python training - (2006-06-12)
  [767] Finding the language preference of a web site visitor - (2006-06-18)
  [800] Effective web campaign? - (2006-07-12)
  [893] Visibility - (2006-10-14)
  [916] Driving customers away - (2006-11-07)
  [976] Santa at the station - (2006-12-09)
  [994] Training on Cascading Style Sheets - (2006-12-17)
  [1029] Our search engine placement is dropping. - (2007-01-11)
  [1055] Above the fold - (2007-01-28)
  [1104] Drawing dynamic graphs in PHP - (2007-03-09)
  [1177] Sorting out for a site map - (2007-05-05)
  [1184] Finding resources - some pointers - (2007-05-13)
  [1186] Two new pages / sites - (2007-05-14)
  [1198] From Web to Web 2 - (2007-05-21)
  [1207] Simple but effective use of mod_rewrite (Apache httpd) - (2007-05-27)
  [1212] What brought YOU to our web site? - (2007-06-01)
  [1237] What proportion of our web traffic is robots? - (2007-06-19)
  [1297] Stuffing content into a web page - easy maintainance - (2007-08-09)
  [1437] Above the fold with First Great Western - (2007-11-19)
  [1494] A time to update pictures - (2008-01-03)
  [1505] Script to present commonly used images - PHP - (2008-01-13)
  [1506] Ongoing Image Copyright Issues, PHP and MySQL solutions - (2008-01-14)
  [1513] Perl, PHP or Python? No - Perl AND PHP AND Python! - (2008-01-20)
  [1534] Where in the world / country is my visitor from? - (2008-02-07)
  [1541] Colour, Composition or Content - (2008-02-16)
  [1554] Online hotel reservations - Melksham, Wiltshire (near Bath) - (2008-02-24)
  [1610] PHP course dot co, dot uk - (2008-04-13)
  [1630] To provide external links, or not? - (2008-05-04)
  [1634] Kiss and Book - (2008-05-07)
  [1653] How do Google Ads work? - (2008-05-25)
  [1711] Rapid growth leads to server move - (2008-07-17)
  [1747] Who is watching you? - (2008-08-10)
  [1756] Ever had One of THOSE mornings? - (2008-08-16)
  [1793] Which country does a search engine think you are located in? - (2008-09-11)
  [1797] I have been working hard but I do not expect you noticed - (2008-09-14)
  [1833] Web Bloopers - good form design - avoiding pitfalls - (2008-10-11)
  [1856] A few of my favourite things - (2008-10-26)
  [1888] Find the link - (2008-11-16)
  [1955] How to avoid duplicating web page maintainance - (2008-12-20)
  [1961] Making our things easier to find - (2008-12-26)
  [1970] Plagarism - who is copying my pages? - (2009-01-02)
  [1982] Cooking bodies and URLs - (2009-01-08)
  [2056] Web Site Loading - experiences and some solutions shared - (2009-02-26)
  [2065] Static mirroring through HTTrack, wget and others - (2009-03-03)
  [2225] How important is a front page ranking on a search engine? - (2009-06-09)
  [2332] Formation, des langages Open Source - (2009-08-09)
  [2333] Formaci[83][c2]ón, de los lenguajes de c[83][c2]ódigo abierto - (2009-08-09)
  [2334] Formazione, Open Source computer lingue - (2009-08-09)
  [2335] Ausbildung, die Open-Source-Sprachen - (2009-08-09)
  [2336] Forma[83][c2]ç[83][c2]ão, Open Source computador l[83][c2]ínguas - (2009-08-09)
  [2337] Opleiding, Open Source computertalen - (2009-08-09)
  [2338] Uddannelse, Open Source computer sprog - (2009-08-09)
  [2339] Oppl[83][c2]æring, Open Source datamaskinen spr[83][c2]åk - (2009-08-09)
  [2340] ldning, Open Source dator spr[83][c2]åk - (2009-08-09)
  [2341] Koulutus, Open Source tietokone kielill[83][c2]ä - (2009-08-09)
  [2389] Writing with our customers words - (2009-09-01)
  [2410] Removal of technical resources from this site - (2009-09-19)
  [2519] Status Page / breaks of service in early December - (2009-11-30)
  [2532] Analysing Google arrivals by country of origin - (2009-12-10)
  [2552] Web site traffic - real users, or just noise? - (2009-12-26)
  [2569] How to run a successful online poll / petition / survey / consultation - (2010-01-10)
  [2668] Is it worth it? - (2010-03-09)
  [2981] How to set up short and meaningfull alternative URLs - (2010-10-02)
  [3022] Retaining web site visitors - reducing the one page wonders - (2010-10-31)
  [3087] Making the most of critical emails - reading behind the scene - (2010-12-16)
  [3149] Looking back at www.wellho.net - (2011-01-28)
  [3197] Finding and diverting image requests from rogue domains - (2011-03-08)
  [3367] Google +1 - what is it? - (2011-07-22)
  [3426] Automed web site testing scripted in Ruby using watir-webdriver - (2011-09-09)
  [3491] Who is knocking at your web site door? Are you well set up to deal with allcomers? - (2011-10-21)
  [3532] Sharing the user experience - designing a form with the customer in mind - (2011-11-29)
  [3554] Learning more about our web site - and learning how to learn about yours - (2011-12-17)
  [3623] Some TestWise examples - helping use Ruby code to check your web site operation - (2012-02-24)
  [3734] QR codes with marketing logos embedded - (2012-05-16)
  [3744] Short Web Addresses for Melksham - (2012-05-30)
  [3745] Legal change - You need to obtain user consent if you use cookies on your website - (2012-06-01)
  [3776] Some traps it's so easy to fall into in designing your web site - (2012-06-23)
  [3896] An email marathon - (2012-10-15)
  [3974] TV show appearance - how does it effect your web site? - (2013-01-13)
  [4001] Helping search engines with appropriate 400 error codes - (2013-02-11)
  [4076] Web site - fully back! - (2013-04-29)
  [4115] More or less back - what happened to our server the other day - (2013-06-14)
  [4136] How do I post automatically from a PHP script to my Twitter account? - (2013-07-10)
  [4239] Facebook marketing - early experiences - (2014-01-19)
  [4376] Well House Consultants, Well House Manor, First Great Western Coffee shop, TransWilts / 2014 web site reports - (2015-01-01)
  [4401] Selecting RECENT and POPULAR news and trends for your web site users - (2015-01-19)
  [4474] Effect on external factors on traffic to our web sites - an update - (2015-04-26)
  [4492] Almost so wrong, but perhaps it's right for some? - (2015-05-11)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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