Jpeg – A jpeg, which was named after the group that designed it – Joint Photographic Experts Group – was first developed in 1986. It can reduce the size of a file by 15% without sacrificing quality of the image.
When to use a Jpeg? When a small file size is more important than achieving the maximum quality of an image, use a jpeg. Great to use for photos uploaded to websites and Facebook.
Psd – Photoshop Document, or psd file, is the file extension given to an image that can be opened in Photoshop. If you need to make changes to an image, then you will likely need the psd file to do so. By having it you can edit the image in Photoshop, and then convert the file to a jpeg, png or whatever file type you wish.
When to use a Psd? When you hire someone to design an image in Photoshop and may need to edit it later on.
Gif – Created in 1987 as a means to quickly move images across slow internet connections, a gif file is smaller than a jpeg and contains fewer colors (up to 256). Gif, which is pronounced with a ‘j’ like ‘jif’, means Graphics Interchange Format.
When to use a Gif? Gif files are one of the most widely supported formats for animated images and have extremely small file sizes (due to the limit on colors). Gifs are ideal for simple images or icons, animations and web graphics that contain a small amount of colors.
Png – Portable Network Graphics, or png file, was developed in the mid 90’s as an alternative to gif files. While generally not ideal for animations or maintaining a small file size, png files are superior to gif files in two ways: they have better compression and the ability to contain millions of colors.
When to use a Png? When you need a complex, colorful image with a transparent background (like a logo for a website) a png file is your best choice.