Have you even been confused about which file format to use when saving your images? Have you ever wondered what the difference between .jpg, or .gif is? Would you like some closure on a bet you made with your friend on what the correct pronunciation is for "GIF"? We'll try to help.
JPG
Jpg or jpeg (pronounced jay-peg) is one of the most common image formats on the web for one main reason. When you export an image to a jpg format through photo editing software, you can determine the file size by the "quality" or compression level. To compress a file means to reduce the bytes of memory it requires. The more the image is compressed or the quality reduced, the smaller the file is. The smaller the file size, the faster a web page will load or an email will display the image. It's a balancing act to determine how small you can get an image without distorting the image noticeably. The rule of thumb for Internet applications is that if it's a photo, save it in jpg format. Jpg file size is determined by how large (in pixels) the image is. If you need to significantly decrease the file size, decrease the actual pixel size first.
The last thing you should know about jpg format is that every time a jpg is resaved the file loses some quality. Therefore, you should never store your original photo in jpg format unless it is set at the highest quality (i.e. smallest compression) possible.
GIF
Gif (the original and preferred pronunciation is jif, but many pronounce this as gif) is another one of the most common web file formats for images. Gif is also a compressed file format, but gif format only stores the actual colors, resulting in a smaller file size for the same stored image compared to jpg. Gif is the preferred format for illustrations, logos or photos with large areas using limited colors. In gif format, you can also choose how many colors to display and even which colors to use. Another advantage of using gifs is the capability to support transparency and animation.
Animated GIF
An animated gif is a file format that allows many images to display in a sequence, like an animated movie. Animated gifs can also be completely different images that display to present a message in 3 or 4 steps, like a banner ad on the Internet. In Gif format you can mimic true animation by displaying several frames in quick succession so your viewer cannot see separate images—like an animated movie. The more frames used, the smoother the animation will appear.
PNG
PNG file format is similar to GIF.
TIF
The tif format is commonly used for printing. Tif is a lossless image format, which means that unlike Jpgs and Gifs, this format does not lose information or introduce noise when resaving the image. Nothing is "lost."
BMP
BMP is a common 24-bit color lossless graphic format for Windows. Unlike JPGs or Gifs, it does not lose information or introduce noise when resaving the image.
