Eyes on Final Fantasy Forums > Reference > Help Forum > The Different Image File Types

[o_O]

It was my understanding that it was every time the image was opened and closed that decompression/recompression occurred. I could be wrong though, that was off of the top of my head.

[Mirage]

If that was the case, they'd get reduced to garbage in seconds on 4chan :p.

[Cleansation]

PNG is the superior format, quality and layers... What more can you ask for ?

Gif's are good for animation and stuff but the quality sucks pretty bad for non moving images.

Jpeg's are just crap but small file size (like jpeg) and for some reason the most commonly used format.

[Evastio]

So basically TIFF is good for preserving the quality of images but not space while with JPEG it's the opposite?

Originally Posted by o_O ^

It was my understanding that it was every time the image was opened and closed that decompression/recompression occurred. I could be wrong though, that was off of the top of my head.

So you don't know that for sure? Because if that is true then that means that PNG is much better for sigs than JPEG. Personally, I haven't noticed anything too noticable when changing a sig image from a PNG to JPEG file or when I save a JPEG sig image repeatedly.

[o_O]

Nope, I don't know it even slightly for sure. Mirage's point is valid, and if someone presented both hypotheses to me for the first time now, I'd think that whoever came up with mine was on drugs. It's just what I always thought, but I also always thought it was a bit ridiculous.

Note that even if my hypothesis were true, it wouldn't mean that a sig image would be degraded, since the image that is displayed on a client monitor is downloaded to their computer first, not opened on the server. Also, you'd need to do it a stupid number of times. Like, and unbelievable number.

Tiff is good for anything really, but not great. PNG is fantastic at being a good image format.

[rubah]

I'm pretty sure the compression is written into the jpeg file. maybe jpeg2000 has some of that weird stuff, but you can just open a file in an editor and it will be the same every time. Which even if it's not written into the file and is written into the algorithm, comes out to the same result so the point is moot.

[o_O]

The more I think about it, the more ridiculous it seems that a JPEG would be decompressed and recompressed every time you open it. Why would a simple picture viewer have the algorithm to compress a JPEG built into it?

I even performed bitwise editing of a JPEG image at university.

[Mirage]

Originally Posted by Cleansation ^

PNG is the superior format, quality and layers... What more can you ask for ? :p

Gif's are good for animation and stuff but the quality sucks pretty bad for non moving images.

Jpeg's are just crap but small file size (like jpeg) and for some reason the most commonly used format.

The reasons are quite obvious. First, you'll have trouble telling a high quality JPEG compressed photograph from one stored in PNG. Second, photographs don't really need layers. Third, a 6 MP PNG image would be gigantic. They would take forever to send over the internet over the average internet connection, and you'd only fit what, 20 images on a 1 GB memory card? Something like that.

Actually, a bit more. I just did a test, and i ended up with 13 MB for a 6 MP image.

Don't get me wrong though, PNG is good, but it's not practical to use in all situations. I use PNG for my own graphical works, but i convert them to JPEG when I upload them to the internet.