Another commonly seen mistake in text design is the use of large or small font sizes as the body text of a page. Page designers sometimes think that the default text in their browser is wrong for the effect they want to achieve, and it is certainly acceptable to make a small percentage of the text on a given page large or small, as appropriate. It is not recommended to change the font size of all the text on a page since the user must be assumed to have set the default font size in his or her browser to exactly the size that is most comfortable for that user on his or her monitor. Any other font size is thus by definition suboptimal for reading body text. It is quite common to use thumbnail versions to represent images that are too large to be downloaded without a specific user request.
Thumbnails are smaller, meaning that more can fit on a page and that download times are minimized.
Unfortunately, the two most common ways of reducing images, scaling and cropping, both result in thumbnails that can be hard to interpret, as shown in the figure. Three different ways of making thumbnails. Scaling reduces the image so much that pictures with extensive detail wash out and become too crowded to be meaningful. Cropping preserves those details that are within the new viewport, but at the cost of losing the context of the image as a whole. My recommendation is to use a combination of cropping and scaling, resulting in a technique I call relevance-enhanced image reduction .