Screenshot brightness

[TOK]

Sorry if this has been covered, I searched here and Google but didn't find any info. A buddy and I have been sharing high score screenshots on various games.
His are all dimmer than mine, and I'm not totally sure why.

Here are examples from Robotron... First mine:


Here is his:


Now, for Robotron, I'm using .99 and the new ROM, he hasn't upgraded from .84 yet. That means mine is a .png file and his is a .jpg. Is there that much of a difference of image quality between the formats?

What I'm curious about is where MAME actually takes the snaps from. Do any video card settings like refresh rate, etc change the quality/brightness of the screenshot? I didn't figure they would, but something is going on.

Thanks for any insight!

[elvis]

One of you paused the game to take a screenshot (dimming the image), and one didn't.

Either that, or one of you is controlling the game brighness via the blitter software and/or MAME -full_screen_brightness switch, and one is controlling the brighness by the monitor hardware.

[TOK]

Thanks Elvis. We got to the bottom of it quick... His version of MAME does the snaps as .png files and he was converting them to .jpg.

(Anyone looking at the screenshots in my first post won't see the original problem now as I updated the link with the brighter version.)