In multiMAN there are three different ways to take a screenshot:
- inside multiMAN, press PS button, go to Photo's column and select "Save a screenshot [multiMAN]". It will be stored and viewable directly in the XMB.
- Button combo : Start + R2
- Telnet to PS3 IP, port 8080 : screenshot
Last two options save the picture on /dev_hdd0/Date-Time-SCREENSHOT.RAW
Outside of multiMAN, I don't think it's possible.
It would be great if the multiman's XMB screenshot menu were available in games too. Maybe it is in newer version of multiMAN? (I'm still using an old one).