The technical explanations of gamma are irrelevant here the visual effect of changing gamma values is easy to see. Images will change noticeably with even minor changes in gamma settings. In the Windows version of Photoshop the gamma control only applies to images within Photoshop windows , not to the global display environment as it does on the Macintosh. Thus a line of 12 point Times type on a Macintosh looks more like 14 points in Times New Roman on a windows machine.
Every Web browser interprets HTML tags a little differently.
Tables, forms, graphic positioning and alignment tags will all work a bit differently in each brand or version of Web browser. Normally these subtleties might pass unnoticed, but in very precise or complex Web page layouts they can lead to some nasty surprises. But never trust the implementation of any of these advanced features until you have seen your Web pages displayed and working reliably in each brand of browser. Graphics offset variations Beware of trying to get a graphic imbedded on your page to line up precisely with a page background image. Offset variations make it a losing cause.