Web page dimensions are measured by pixels. More to the point, the pixels the pages are optimized for. For many years the standard was 1024 x 768 pixels. Today, higher resolutions like 1366 x 768 are commonplace. 1280 x 1600 is also becoming popular. This is due to the rise in number of large monitors.
In 2012, studies showed that 85% of computers users use resolutions higher than 1024 x 768. 13% use 1024 x 768. Less than 1% use 800 x 600. Over 98% use over 16 million colors.
Another way to measure web page dimensions is by the banner size. These are the dimensions used when placing ads on a web page. There are many types of banners. Sizes are in pixels. The most common are medium rectangle at 300 x 250 pixels, while the square pop-up is 250 x 250.
There is also the vertical rectangle (240 x 400), large rectangle (336 x 280) and rectangle (180 x 150). There is also the 3:1 rectangle at 300 x 100 pixels. The pop under is 720 x 300.
A full banner is 468 x 60, while the half banner is 234 x 60. A micro bar has dimensions of 88 x 31. Button 1 is 120 x 90 while button 2 is 120 x 60 pixels. A vertical banner is 120 x 240 pixels. A leaderboard measures 728 x 90.
Image Specs on Web Pages
Dimensions have to be smaller than those used for print. Although broadband use is increasing, there are still many users with slow Internet connections, hence the need for images to load quickly. The most common format used is JPG, although there are still some GIF and PNG images online.
GIFs are often used for animated images, although their use is decreasing with the advent of animation. JPGs are more popular because there is little image quality loss even when the file is compressed. This feature makes it easy to reduce web page dimensions. Digital cameras usually output their images in JPG format.
The images on digital cameras are very high. Once transferred on a computer they can take several megabytes of space. If you want to post them online, the file size has to be reduced. If you are going to put a lot of images on your site, its dimensions will increase. You can make things easier for the user by creating thumbnail galleries for the large images.