I don't think this calculation is correct since it would be determining the size of a raw bitmap (not JPEG) at 32-bit color depth. We are saving images as 24-bit JPEG's. However, it probably is not a bad idea to over-estimate this number because there's no guarantee as to what the compression ratio will be for the JPEG. If nothing else though, I think we should be multiplying by `3` here instead of `4` (that would give us the size of a raw bitmap at 24-bit color depth).