The width and height of the image in pixels. I'll re-open it by going back up to the Image menu and choosing Image Size: Step 1: Find the total number of pixels in the imageįirst, we need the total number of pixels, and we find that in the Image Size dialog box. So to figure out the file size of an image, all we need to do is take the total number of pixels, multiply it by 3, and we have our answer! Here's how to do it. It's always 3 bytes for every pixel one for red, one for green and one for blue. But the amount of memory that each pixel needs doesn't change. Of course, most images contain millions of pixels, not just 10. For example, if your image contained 10 pixels, each pixel would need 1 byte for red, 1 byte for green and 1 byte for blue, for a total of 3 bytes. Learn more about RGB color and color channels in Photoshop How do color channels affect image size?Įach of the three color channels (Red, Green and Blue) takes up exactly 1 byte in memory for each and every pixel in the image.
All colors in your image are made by mixing red, green and blue.
