Last week we published this funny riddle for your friends to solve and took that opportunity to briefly explain what pixels are, and we ended up talking about some interesting things such as color depth and zeros and ones.
After having introduced some important concepts and basic ideas in that post, let’s start today by looking at the most popular image formats.
Also called JPG (Joint Photographic Experts Group), this format allows to compress images with different compression levels. JPEG is ideal for the Web where load times and data transfers are so important.
When you have a very heavy image (let’s say 2 MB) and you’ve got to upload it to the Internet, a good idea is to save it as a JPG. This way, you’ll be applying the JPEG compression algorithm and your new compressed file will take up less storage space than the original one.
Have you ever entered a website and noticed that some images were loading slowly, and their quality progressively improved as that web page was loading? Sure you have! Those were JPG images being loaded in progressive mode, which is one of JPG’s greatest features.
JPG uses a 24-bit color depth, allowing you to store up to 16.7 million different colors.
As with JPG, PNG is able to compress files too, however, PNG compression doesn’t have any impact on the image quality because it uses lossless techniques.
In case you don’t know there are mainly two ways intended to compress images, they are called lossy and lossless. JPG is lossy, whereas PNG and GIF are lossless.
Lossy means that the algorithm performed removes some image details during the compression process (those ones considered unnecessary); instead, lossless allows to retrieve the information when the image is decompressed.
PNG supports palettes of 24-bit RGB color as well as palettes of 32-bit RGBA color, and was originally designed in order to improve those limitations imposed by the GIF format. Last but not least, one of PNG’s most important features is that it supports transparency.
This format is a good choice for when you have an image with very few colors. Unlike JPG, GIF doesn’t implement any lossy compression algorithm (in that sense, GIF and PNG are quite similar) and only uses 256 different colors. One of its main advantages is that GIF allows animations.
TIFF (Tagged Image File Format) is a file format mostly used by graphic designers, artists and photographers. It requires a lot of space on the hard disk since it allows to store high-quality images.
TIFF allows you to encode your files by using an uncompressed palette of 32-bit CMYK color as well as a palette of 24-bit RGB color.
Which One Should I Use? JPG, PNG, GIF or TIFF?
After all, the format that better suits you depends on how you are using your particular images.
Are you a web animator and need to make a simple animation using few colors? If your work has to be uploaded to a web page then you may be interested in the GIF format.
Remember: GIF is the only one supporting animations. Since it uses 256 colors, the resulting image won’t eat your hard disk space and the Web will be able to smoothly process it.
On the other hand, if you need for example to upload a heavy picture with many many colors to your blog, you should first choose between the JPG format and the PNG format and then compress your file. Never use TIFF in this case because as noted before, TIFF is an uncompressed format requiring much disk space and therefore it’s not suitable for the Web. This is the best choice for graphic designers wanting to store their high quality images into their hard drives.