[PIL]: Image size in runtime

[Scott David Daniels]

Andrea Gavana wrote:
> I am using PIL to load and display some pictures (via wxPython) in a
> GUI. I have added the ability for the user to change the linear
> dimensions of the image (in pixels) and the quality of the image in
> order for the image to be saved in another file.
> I was wondering if is there a way to know in advance, based on the
> pixel dimensions specified by the user and by the image quality, which
> file size (in
> bytes) I will obtain for the new image (approximatively). Is there a
> way to obtain such result without actually saving the image?

The answer is really no, since it depends on the complexity of the
picture.  A solid square of one color is highly compressible, and a
photo of a tall ship's rigging is relatively hard to compress.  You
can compress to a cStringIO file (and so not have to actually hit
the disk) to get a size, ten discard the cStringIO object.

-- 
--Scott David Daniels
scott.daniels at acm.org