IMAGES ARE STILL MALFUNCTIONING
Posted: Thu Nov 03, 2016 1:18 pm
The software running this board has been somewhat obstreperous as of late with image management, something with which the SYSOPs are aware. This post is a test of some image uploads. I'd like to be able to resume updating my F7 build log but won't be able to do so if I am not able to post satisfactory images.
All uploaded files were generated from a monochrome GIF87A image, originally 4608 × 2466 × 2, and reduced to a 1024 x 548 uploaded image size.
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The first upload I attempted was a reduced copy of the GIF source file. The upload failed with the error "Image file type mismatch: expected extension jpg but extension gif given." This error has been consistently occurring ever since the board software was upgraded. Of the three on-line forums in which I participate that run on PHP-BB software, this one is the only one that has a problem with GIFs. The other boards run an older version of PHP-BB, making me suspect the upgrade introduce some inadvertent bugs.
The second upload test was a JPEG.
The upload completed but when I viewed the image during preview of my message the board presented it at the size 548 x 293, not at the uploaded size of 1024 x 548. The board is reporting the image's file size at 40KB, which is also wrong—the file that was uploaded is 139KB. In other words, PHP-BB truncated the file during storage. Aside from size being wrong, JPEG is not a good format for storing monochrome images or images with eight bit color, as the resulting file is bulky despite no or little color information being present. Also, compression in JPEG is "lossy," causing degradation of image quality. It is for these reasons I usually upload GIFs to public forums, even though GIF color rendition is not as fine as some other image formats.
The third upload test was a PNG.
As can be seen, that upload was successful as well. However, going from GIF to PNG caused a substantial degradation of image quality. PNG was originally developed as a way to get around the LZW compression algorithm patents that encumbered GIFs. Those patents expired in 2004, so there is no particular reason to use PNG, other than its higher color resolution.
The final upload test was a TIFF. It turns out Chaski doesn't accept TIFFs.
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All uploaded files were generated from a monochrome GIF87A image, originally 4608 × 2466 × 2, and reduced to a 1024 x 548 uploaded image size.
—————————————————————————————
The first upload I attempted was a reduced copy of the GIF source file. The upload failed with the error "Image file type mismatch: expected extension jpg but extension gif given." This error has been consistently occurring ever since the board software was upgraded. Of the three on-line forums in which I participate that run on PHP-BB software, this one is the only one that has a problem with GIFs. The other boards run an older version of PHP-BB, making me suspect the upgrade introduce some inadvertent bugs.
The second upload test was a JPEG.
The upload completed but when I viewed the image during preview of my message the board presented it at the size 548 x 293, not at the uploaded size of 1024 x 548. The board is reporting the image's file size at 40KB, which is also wrong—the file that was uploaded is 139KB. In other words, PHP-BB truncated the file during storage. Aside from size being wrong, JPEG is not a good format for storing monochrome images or images with eight bit color, as the resulting file is bulky despite no or little color information being present. Also, compression in JPEG is "lossy," causing degradation of image quality. It is for these reasons I usually upload GIFs to public forums, even though GIF color rendition is not as fine as some other image formats.
The third upload test was a PNG.
As can be seen, that upload was successful as well. However, going from GIF to PNG caused a substantial degradation of image quality. PNG was originally developed as a way to get around the LZW compression algorithm patents that encumbered GIFs. Those patents expired in 2004, so there is no particular reason to use PNG, other than its higher color resolution.
The final upload test was a TIFF. It turns out Chaski doesn't accept TIFFs.
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