That's just how the PS1 game is stretched to best fit the screen.
It's not a malfunction in the ROM, that's how it's supposed to be.

You can change it by pressing [Home] and changing the screen settings/

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Short answer: See PJ's post

Long answer:
No, it's not due to the compression at all. It's due to the limitations of the Snoy emulator. PS1 games output to 640×480 pixels (I'm using NTSC here, adjust if you live in PAL areas), but the PSP's screen is 480x272. In order to prevent weird streching, Sony desided to cut the screen size in half. So, the output of the ps1 emu is 320x240, exactly the same size that you see on your psp screen.

If you want to play with the streching, hit the home button, and under "Settings" you can adjust the screen size. Here is what the options do, as far as I know.

• Fullscreen-changes the output full screen. "Letterboxes" (i.e., small black bars) it a bit to fit the 16x9 ratio.
• Original-the 320x240 I just discribed above.
• Normal-Streaches it a bit, and smooths out the picture
• Zoom-Streches the picture even futher so that the width is equal to the width of the screen size.

Mind you, none of these modes ever make the emulator output a "better" picture with more pixels defined. They are all just streching of the 320x240 screen. I think this is because the psp is at it's limits, and rendering the extra pixels would lag the game too much.

Note: I think the "Zoom" option is only on the 3.10 ps1 emulator only.

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