Originally Posted by Ghabby
I don't mean to butt in here, but just a little addition to what Domino said. For future reference, if you're working with an image that is large (say 800x or more), jpg is probably a good filetype to rely on. JPEG, when exported correctly is a nice format because of the compression capability offered, especially done from photoshop. Programs like MSPAINT take compression to the max, and you can easily notice the loss of quality in jpeg files. The cool thing about jpeg files, is that when used as something like a photograph, the loss of quality is virtually unnoticeable. Call it a balance of quality and filesize. Hence why we usually save screenshots as Jpeg, and they are rarely bigger than 150-200kb.
For images that are smaller (usually less than 800x), png is in fact a good format to use. PNG files are usually a little bigger than jpeg files, but offer a lot higher quality. PNG files are excellent for vector images, and things that require attention to detail.
To compliment this little lesson, just remember that JPEG files are considered "lossy" because of the compression. PNG files are considered to be "lossless" because of the exact opposite. Keep that in mind, and you'll always pick the right format for your image.
Reply With Quote