Size of images

[Steph]

Please can you tell me the relationship between the filesize of an image when displayed in image size in Photoshop and the filesize which shows in Explorer? as these are never the same - sorry it is not directly related to PTE but you chaps seem knowledgable on all aspects of digital imaging!!

Thanks

Steph

[fh1805]

Steph,

There are so many different parameters involved, no two "readings" will ever be the same. Explorer gives you the size of the file in terms of how many bytes, Kilobytes, Megabytes, etc. the file occupies on the disk. Photoshop Image Size is giving you how many bytes, Kilobytes, Megabytes of memory (RAM) the image occupies.

Two examples from a sequence I'm currently working one:

Image1 - Explorer = 281K, Photoshop = 5.79M - Photoshop is bigger than Explorer

Image2 - Explorer = 157M, Photoshop = 49.9M - Explorer is bigger than Photoshop

Image1 is a JPEG. The file on disk is heavily compressed. The file in memory is heavily expanded.

Image2 is a PSD. The file on disk holds 9 layers that have been "stitched" into a panorama. The stitched image takes up 49.9MB in memory.

You see, no easy answers. You have to understand just what each file is - and isn't. And also what each number relates to - or doesn't.

regards,

Peter