Re: Desperately needing direction with saving images under different compression/quality schemes

Martin,

Thank you for your response, however, i think i wasn't able to explain
myself properly :). All i really need to be able to do is predict what
changes are made to the pixels in an image by various graphics/image
manipulation programs.

At the end of the day, to use another example, if you have a file of 91
KB's and open it in ms paint, then save it without making any changes
yourself, that file becomes 77 KB's. And even if you reopen the 77 KB
image in ms paint and resave it again, it will still be 77 KB's (no
further changes to pixels, maybe just a few bytes of changes in headers
& meta data from resaves, but thats it). Doing this over and over again
on each new image produces the 77 KB image with no pixels changed.

What i need to be able to do is figure out what ms paint is doing when
the file is changed from 91 KB's to 77 KB's. I really just need to know
what types of changes are occuring or would/could occur between this
process/transition.

Once i do figure this out, i can experiment with thousands of different
combinations to figure out the extent to which these changes are
applied (ie: compression at 90, 89 or 88 etc etc). But given my
background is not in image processing, i am not sure what these changes
are, maybe colordepth, soem compression/quality changes, perhaps other
things i am unaware of that do occur by default...? thats all i really
need to know, the type of changes, not necessarily the extent to which
each particular type of change is applied (i can figure this out later
at my own accord).

Thank you, i hope that clarifies things somewhat.

.

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