I am writing a Technical Design Document and starting to list assets and their file sizes.
The formula for calculating the file size of a PNG is easy: width x height x bit depth.
I am having a problem with the file size windows shows in the file properties for some of my png's.
The dimensions are 1280 x 720 32bit and filesize ought to be 3,686,400B. Windows Properties shows 3.6KB. Shouldn't this be 3600KB?
Now I have a cursor image:
32 x 32 32bit ought to be 4,096B. Why does the file properties in windows say the file size is 304B?
As you can see the size on disk is correct for the cursor but the size is off. With the background image the size is correct but the size on disk is bigger.
I am using GIMP to create the images and exporting with none of the tick boxes checked, so no comments or background colour saved etc.
Can anyone explain why windows does this? Thank you.