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Odd 404 error...
Posted: Thu Mar 10, 2005 2:36 pm
by Todd_Z
I track my 404's in an error log, and for some reason the Bg.jpg for my site comes up as a 404 often - any idea about why this is and how/if i can fix it? Maybe a php file that keeps trying to get the image if its locked somehow... I don't even have an idea...
Posted: Thu Mar 10, 2005 2:45 pm
by feyd
If you look through your access logs, you should find what page/script is referencing it. It may be as simple as a case issue, or permissions problem..
Posted: Thu Mar 10, 2005 3:29 pm
by Todd_Z
Thats the odd part - I log which pages are referencing the Bg.jpg, but when I go to those pages it works... its just randomly sometimes they fail...
Posted: Thu Mar 10, 2005 3:32 pm
by feyd
is this a dynamically created file, or a large file? What variant of JPEG is it?
Posted: Thu Mar 10, 2005 3:35 pm
by Todd_Z
Its as traditional as an image could possibly be ->
http://www.acdrifter.com/Bg.jpg
Posted: Thu Mar 10, 2005 4:08 pm
by feyd
why is your 4x4 image 12K ? btw, the block size in a JPEG is 8x8 for the cosine transform area.
Posted: Thu Mar 10, 2005 5:57 pm
by Todd_Z
a. idk why its 12k - is that a lot?
b. 8*8 why?
Posted: Thu Mar 10, 2005 6:14 pm
by feyd
That's the size the consortium chose for the cosine transform (CST) system. Once you get down into the nitty-gritty of the standards you'd understand.. I'll try to explain. The average picture doesn't change a whole lot over an 8x8 area. Therefore, if you are converting the bitmap data into a math equation describing the wavelength changes in the various directions possible through the block, it becomes a simpler equation. The more compression you ask for, the more basic the equation becomes too. This is why data is lost.
12K for a 4x4 image is huge. Fully uncompressed into memory, that image should only consume at most 64 bytes. That's with storing 32-bit values for each pixel and memory padding. Even a 8x8 fully uncompressed will consume 256 bytes with memory padding.