ABC writes:

Is there any way I can keeep jpg file at the same size?

This is any 170K jpg. All I did was to have flipped it horizontally
. It then saved as a 340K file at 100%.

I thought, for flipping, the software only re-arranged the pixels.
What can i do if I want to keep jpg at small size?

What software did you use, and what exact command? Ordinary
photo-editing software doesn't support the lossless rotation
capabilities mostly; that's mostly supported in viewing and organizing
software (like Irfan View and Thumbs Plus). If you do use the
lossless rotation commands, the file size changes *very* little (I
don't understand why it changes *at all*, but in my experience it
does; but only very little, like 1% or something).

I *think* what you did was opened the file in a photo-editor, flipped
it, and then re-saved at top jpeg quality. I suspect the file
*wasn't* at top jpeg quality originally, and that explains the
increase in size.

does it mean only the original JPG is the smallest?

Nothing too magical about the original.
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