Why does resaving same file make it smaller first time?

theTinker

Anyone know the exact reason why saving a picture/jpg with PAINT on my windows computer is MUCH smaller than my camera saved file. I make no modifications to the file.

Is it using the more powerful cpu to do more complex algorythms? Is it reducing the quality using some preset compression ratio that is of lesser quality than my Canon 450D camera? Is it something else?

It doesnt seem to happen if i resave it multiple times so i dont think its lowering quality each cycle, perhaps its reached its compression ratio limit?

MrJoeSoap

I'm not a total expert on this but I always imagined it was because the Paint jpeg is a more highly-compressed / lower quality image.

luisspellcast

using paint to save your photos it's like putting out fire with ketchup or mayo...

to answer your post, the reason why paint can't save your images with full quality it's because it doesn't support more than 24-bit image processing

look for a program with raw file support and you won't have any more problems

stcstc

its the compression level that pain is using


btw 24bit colour is all that a jpg supports, ie 8bits per chanel