From a disc? Umm, no. The Wii can't even read CDs. The thing can read DVD images and Wii/GCN discs, but a PSX ISO is gonna be in a pretty different format.
The wii's dvd drive can only read dvds and not cds, so it cant read PSX games, or burned cds either.
There is PSX emulator called WiiSX, and that will be able to play games from burned onto DVD, or dumps transferred onto SD or USB.
I don't think trimming PSX isos is possible, because I dont think they have any rubbish data to nake up the space like wii/ds games. When you dump a PS1 game it dumps to however big the game is, which is usually under 700 megabytes (the maximum approx).
It may be possible to compress the ISO's though, however that has not been implemented in WiiSX yet and may not provide significant savings (I haven't really tried).
There is PSX emulator called WiiSX, and that will be able to play games from burned onto DVD, or dumps transferred onto SD or USB.
I don't think trimming PSX isos is possible, because I dont think they have any rubbish data to nake up the space like wii/ds games. When you dump a PS1 game it dumps to however big the game is, which is usually under 700 megabytes (the maximum approx).
It may be possible to compress the ISO's though, however that has not been implemented in WiiSX yet and may not provide significant savings (I haven't really tried).
Wat you're forgetting here is that the entire wii disc is encrypted, the reason you can "trim" wii discs is because when you encrypt a bunch of zeroes you obviously end up with a bunch of other crap instead of the zeroes, making it impossible to compress (it's just random data, no patterns)
They probably did this to make transferring isos over the internet of Wii games harder, but of course you can just replace the encrypted data with your own compressible pad if you know where the bounds end.
On a normal CD this is not the case, an iso image will be whatever the size of the files contained in the disc, and not automagically the full image.
So when your friend brought you over that 40mb iso, it's because they probably only put 40mb on the gamedisc, or someone went through it with winrar and deleted all the crap that wasn't needed on the disk, old demos, video game trailers, the ten network install, watever. I used to install windows from a CD on machines without cd drives by making multipart rars of the windows install directory on the setup cd (nothing else) and then copying over the files one by one and unraring them in the end. So even though all windows cds have typically been pretty full, much of it wasn't stuff you needed for the install so you could trim it quite a bit.
Now, Playstation games... these were already trimmed at the developer, they contain no game demos, movies, trailers, etc. The discs were probably engineered to even have data in places where it would be most conveniently accessed by the laser, and thusly you will not see any scrubbing techniques that work on them as they work on wii discs, because the concept of it is completely different- They put only what they need for the game on the disc. I mean, sure, I'm not saying it's "not possible" but I am saying it's not the "same situation" as it is with Wii discs, and you can't really think of it in the same terms.
They probably did this to make transferring isos over the internet of Wii games harder, but of course you can just replace the encrypted data with your own compressible pad if you know where the bounds end.
On a normal CD this is not the case, an iso image will be whatever the size of the files contained in the disc, and not automagically the full image.
So when your friend brought you over that 40mb iso, it's because they probably only put 40mb on the gamedisc, or someone went through it with winrar and deleted all the crap that wasn't needed on the disk, old demos, video game trailers, the ten network install, watever. I used to install windows from a CD on machines without cd drives by making multipart rars of the windows install directory on the setup cd (nothing else) and then copying over the files one by one and unraring them in the end. So even though all windows cds have typically been pretty full, much of it wasn't stuff you needed for the install so you could trim it quite a bit.
Now, Playstation games... these were already trimmed at the developer, they contain no game demos, movies, trailers, etc. The discs were probably engineered to even have data in places where it would be most conveniently accessed by the laser, and thusly you will not see any scrubbing techniques that work on them as they work on wii discs, because the concept of it is completely different- They put only what they need for the game on the disc. I mean, sure, I'm not saying it's "not possible" but I am saying it's not the "same situation" as it is with Wii discs, and you can't really think of it in the same terms.
