Pic Compression and File Sizes

Post by **haas mark** » 2003-10-11 06:48am

For some reason, my computer saves images at very large file sizes, and I don't know why. For example, I just made a wallpaper that had all of about 20 colors, at 1024x768 resolution. It's 477 kb. I don't *think* it should be that big.. but anyhow.. is there a way to fix this, and if not, is there something that I can use to make file sizes smaller?

~ver

Hethrir · Post by **Hethrir** » 2003-10-11 06:53am

What format, and what programme are you saving it in? There should be options for JPEG compression to control size vs. quality.

Sir Sirius · Post by **Sir Sirius** » 2003-10-11 07:00am

I once had a bizarre problem with the "Save Picture As..." funktion forcing me to save all images as 24-bit bitmaps despite the original format. Are you talking about something similar?

Post by **haas mark** » 2003-10-11 07:01am

Hethrir wrote:What format, and what programme are you saving it in? There should be options for JPEG compression to control size vs. quality.

PSP 7.04. And I have particular problems with saving GIFs. JPG compression, I could deal with, if it didn't fuck up the picture past lowest compression.

~ver

Hethrir · Post by **Hethrir** » 2003-10-11 07:11am

hmm, that size isn't toobad...have you tried saving it as a BMP then using another programme to save it and see if it comes out a different size? Do you know what pallette you started with? If you use to 8bit colours only in the image it may have a different result.

Post by **haas mark** » 2003-10-11 07:38am

Hethrir wrote:hmm, that size isn't toobad...have you tried saving it as a BMP then using another programme to save it and see if it comes out a different size? Do you know what pallette you started with? If you use to 8bit colours only in the image it may have a different result.

No, I haven't done that......

As for the palette, I HAD to start with a full pallette. But saving as a GIF automatically reduces it to 256 colors.

~ver

Post by **haas mark** » 2003-10-11 08:44am

Another thing I forgot to mention is that my GIFs won't retain transparency in PSP.

~ver

phongn · Post by **phongn** » 2003-10-11 11:12am

That doesn't sound so bad. An uncompressed 5-bit (32-color pallete) 1024x768 comes out to around that size. What format are you using? GIF? PNG? JPEG? TIFF? BMP?

As for JPEGs, if you're doing line art it's best to ignore it. The algorithm does not work well with line art.

If GIFs aren't retaining transparency, you're apparently doing something wrong. What, I'm not sure; I don't really like PSP and have been a PS user for some time. GIF, of course, is forced to reduce to 256 colors. PNG can be 32-bit or 8-bit, depending on your options.

Post by **haas mark** » 2003-10-11 11:17am

phongn wrote:That doesn't sound so bad. An uncompressed 5-bit (32-color pallete) 1024x768 comes out to around that size. What format are you using? GIF? PNG? JPEG? TIFF? BMP?

GIF.

If GIFs aren't retaining transparency, you're apparently doing something wrong. What, I'm not sure; I don't really like PSP and have been a PS user for some time. GIF, of course, is forced to reduce to 256 colors. PNG can be 32-bit or 8-bit, depending on your options.

Actually, for gods only know what reason, I can get it to retain trnasparency in Animation Shop, but not in Paint Shop Pro. o.O And I tinkered with the general settings, and it still didn't do it right.

~ver

Hamel · Post by **Hamel** » 2003-10-11 12:43pm

verilon wrote:For some reason, my computer saves images at very large file sizes, and I don't know why. For example, I just made a wallpaper that had all of about 20 colors, at 1024x768 resolution. It's 477 kb. I don't *think* it should be that big.. but anyhow.. is there a way to fix this, and if not, is there something that I can use to make file sizes smaller?

~ver

How are the colors distributed on the image?

Are there vast areas of one color, or are there unique colors every few pixels?

phongn · Post by **phongn** » 2003-10-11 04:28pm

verilon wrote:
phongn wrote:That doesn't sound so bad. An uncompressed 5-bit (32-color pallete) 1024x768 comes out to around that size. What format are you using? GIF? PNG? JPEG? TIFF? BMP?
GIF.

If you want to use palette-based format, you probably won't get much better than 480KB or so. Try enabling LZW compression for GIF images if you can, or mess with PNGs.

Post by **haas mark** » 2003-10-11 09:03pm

Here is the image in question: http://verilon.free-host.com/vnvnation.gif

~ver

Post by **haas mark** » 2003-10-11 09:04pm

phongn wrote:
verilon wrote:
phongn wrote:That doesn't sound so bad. An uncompressed 5-bit (32-color pallete) 1024x768 comes out to around that size. What format are you using? GIF? PNG? JPEG? TIFF? BMP?
GIF.
If you want to use palette-based format, you probably won't get much better than 480KB or so. Try enabling LZW compression for GIF images if you can, or mess with PNGs.

Uhm.. what exactly is that?

~ver

aerius · Post by **aerius** » 2003-10-11 10:10pm

Shrunk it down to about 180kb with Photoshop, it's now a jpeg. Quality seems decent and I have the jpeg set at medium quality so I can squeeze it down a bit more if needed.

http://members.rogers.com/tlin0252/vnvnation.jpg

Post by **haas mark** » 2003-10-11 10:16pm

aerius wrote:Shrunk it down to about 180kb with Photoshop, it's now a jpeg. Quality seems decent and I have the jpeg set at medium quality so I can squeeze it down a bit more if needed.

http://members.rogers.com/tlin0252/vnvnation.jpg

Cool.. Though it still boggles the mind why it's so big.. I don't understand why, as I've seen more complex wallpapers with smaller file sizes..

~ver

Drooling Iguana · Post by **Drooling Iguana** » 2003-10-11 10:25pm

I got the filesize down to 387k by converting it to PNG. here's the converted image (it's on Angelfire, so you'll probably have to copy/paste it to your URL bar to get it to work). I don't think you're going to get it much smaller than that.

Hamel · Post by **Hamel** » 2003-10-11 11:15pm

verilon wrote:Here is the image in question: http://verilon.free-host.com/vnvnation.gif

~ver

No wonder that's a huge size in gif

Since there are no large areas of a single color, your program can't keep the file size down

phongn · Post by **phongn** » 2003-10-11 11:29pm

Indeed. There's virtually no pattern to the image that can be easily identified, and the text area is rather difficult to compress.

PNGCrush got it down to 340-350KB or so, but that's about the best lossless compression possible.

Post by **haas mark** » 2003-10-11 11:33pm

OK thanks.. but other files (like a 100x100 JPG) I also have problems saving at less that about 10-20Kb at times without losing how it looks.

~ver

phongn · Post by **phongn** » 2003-10-11 11:49pm

verilon wrote:OK thanks.. but other files (like a 100x100 JPG) I also have problems saving at less that about 10-20Kb at times without losing how it looks.

That's a 100x100 JPEG, not a 1024x768 JPEG. Also, we have no idea what the content of the two images may be. You can't simple say "this is a JPEG, it should look virtually lossless when compressed."

You have to compare on a case-by-case basis with the general compression method in mind and then choose what format to use (along with other constraints such as filesize and such).

Post by **haas mark** » 2003-10-12 12:27am

phongn wrote:
verilon wrote:OK thanks.. but other files (like a 100x100 JPG) I also have problems saving at less that about 10-20Kb at times without losing how it looks.
That's a 100x100 JPEG, not a 1024x768 JPEG. Also, we have no idea what the content of the two images may be. You can't simple say "this is a JPEG, it should look virtually lossless when compressed."

You have to compare on a case-by-case basis with the general compression method in mind and then choose what format to use (along with other constraints such as filesize and such).

Well, I mean that it gets really blurry and just fucked up in general. I have ten tons of problems, it seems, with my comp and compression.. and for some reason can't run PS that's better than 6.0.

As well, that's not just 100x100 JPGs.. JPGs in general.

~ver

phongn · Post by **phongn** » 2003-10-12 12:38am

It may be that PSP's JPEG engine is not very good, but at high levels of compression you should expect macroblocking.

Hamel · Post by **Hamel** » 2003-10-12 04:48am

Irfanview has a nice (this is only IMO) jpg compression going for it

If i'm working on a sig, I just save the layered file, c&p a flattened version over to Irfanview and take care of it from there

Einhander Sn0m4n · Post by **Einhander Sn0m4n** » 2003-10-12 05:06am

Hamel wrote:Irfanview has a nice (this is only IMO) jpg compression going for it

If i'm working on a sig, I just save the layered file, c&p a flattened version over to Irfanview and take care of it from there

You forgot about IView's EXCELLENT PNG Compression Engine! Check the filesize on These Three Files.

phongn · Post by **phongn** » 2003-10-12 02:12pm

I usually use Adobe's ImageReady for making PNGs, since I can fine-tune it. Afterwards, I might use PNGCrush to see if that can do any better.

StarDestroyer.Net BBS

Pic Compression and File Sizes

Pic Compression and File Sizes

Re: Pic Compression and File Sizes