A screenshot is an image of your current screen of computer, mobile or high end devices. And if you ever notice all screenshot whether if it’s capture on iPhone, Android, Macbook or PC are always save as .png format.
Now of course you can change the default extension (.png) to something else like jpg or gif, by messing around with device setting. But by default most device saving screenshot in .png format. Do you know why ?
To understand this we, will have to first understand the 3 most common image compression technique ie. jpg, png and gif. Without going into too much technical details here is brief overview:
Jpeg or jpg is for suitable for multicolored photograph like desktop wallpaper, photo taken by camera of some wildlife sanctuary.
Png is best suited for flat-color images like text, logo, clip art etc. Png also support transparency, thus making it ideal for splash images for programs like photoshop.
Gif is similar to png but it also support image animation.
Now let’s come back to the screenshot part. One key thing to note here is, everyone want their screenshot to look sharp and clear. In other words the image should appear like original screen without any loss in picture quality. Here image quality is high preferred over, small file size.
Since most of the time our computer or mobile screen is filled with text and not multi-color scenery, it make sense to use png. Right ? This not only keep the image quality high but within reasonable file size.
Png compression is lossless, ie, what you see, is what you get. However jpg compression results in loss in image quality, depending on level of compression. If we had used jpg instead of png that we would get pixelate or blur images. Whereas gif is not use because png produce same result as gif but within less file size.
See the screenshot that uses jpeg. File size ~40Kb
Not see the same screenshot compressed via png. File size ~100 Kb
As you can see, even though jpg compression can result in small file size, the output quality is too bad to put in any use. Even at same file size png would have been much clearer than jpg. Thus making png as default choice for to save screenshot.
If you have to edit and compress the photo taken by your camera before uploading it to instagram, then use jpeg compression. In this way, your file size will reduce greatly without impacting your image quality too much.
However to upload screenshot of computer or mobile to the web prefer png, for better quality at reasonable file size. While limiting the use of gif to animated images only.