Images on the web differ from those intended for print in several ways. Image resolution for web is usually measured by PPI, pixels per inch, and for print resolution it’s DPI, dots per inch. These measurements are sometimes used interchangeably. Resolution between the two also differs when it comes to size. For instance a professional print would use 300ppi, while for web use, 72ppi would suffice. Another big difference between the two is color mode. When printing an image printers use the CMYK color mode, while web images use RGB due to the display on monitors.
The main image formats that are used for web images are GIF, JPEG, PNG, and, TIFF.
- GIF: These are good when working with a simple design or logo with few colors, however when working with lots of colors such as in a photograph the quality will decrease. Two other features of the GIF would be the animated GIF as well as the ability to include transparency.
- JPEG: Contrary to the GIF, these are a good choice for photograph’s due to the color range and not a good choice for simple design/logo. Also the JPEG is highly compressed so that makes it a good choice for web due to the small size option.
- PNG: The PNG can be looked at as a better version of the GIF. It offers some of the same function as the GIF such as animations and transparency, but with wider range of color and the same small size.
- TIFF: Lastly the TIFF is another full-color format that can be used with original images. The downside to these is that they sometimes can’t be read between programs as well as the file size usually being quite large.