If I have one real pet hate it is the way I see other graphic file formats being incorrectly used on websites. So, here I will attempt to go over the basics just to help out any of my readers who are new to Graphic design and are looking to learn such an art.
Graphic File Formats that deal with Pixels
The simplest point to remember is that there are two separate types of file formats - one is bitmap and the other is vector drawing. Essentially, bitmap images are images made of actual pixels (much like a complex montage), and this is the most common type of image. See the image on this page? That is a bitmap image.
However, bitmaps do have one major flaw. They cannot be scaled up (made bigger) as they then pixelate. This happens because by scaling up, the single pixels that are the build of the image become more pronounced, leading to the infamous jagged appearance. Whilst there are techniques to improve these scaling up again will cause pixelation again and the main method is called anti aliasing. The other best solution to upscale images is by taking/making the original a higher resolution, which actually increases the images file size so takes longer to download/open.
Computer software that you would need to actually produce such files include Adobe Photoshop and its free to use cousin- Gimp, handling file formats such as PNG, JPEG, JPG, TIFF and PSD, just to name a few. The most popular out of these formats for web pages are PNG and JPEG/JPG, the PNG format because of it ability to compress and uncompress and therefore speed up loading time, the JPEG because it allows a full range of colours. It is generally accepted that if you have an image with complex colours and shades etc then you would use JPG. If the image is solid colours and shapes (more or less) then PNG is the way forward for you.
Graphic File Formats that deal with Paths
Vector images differ because they are made up of mathematical paths. This makes vector images crisp, clean and most importantly scale up with no jagged edges. It is for this reason that vector drawings are used for drawing, art and illustration as the final output can be resized accordingly to what the owner of such work wants. Often graphics products such as logos and flyers etc are all done in vector, so if a company decides it wants its logo on the side of a bus/building etc then the scalability wont become a problem.
Abode Illustrator is the graphic design industry standard software to produce vector graphic file formats and the format it often uses is ai.
Well, I hope this makes graphic file formats easier to understand and now when you go to your graphic designer, you will hopefully be able to impress him/her with your new found knowledge about Graphic File Formats. If they don't know what you are talking about then maybe it's time to fire them!
As always I would love to hear what you think.