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We're glad to have a new member of the community!
Momiji 22:29, 12 August 2011 (UTC)
Optimizing print works (Forbidden Scrollery, Wild and Horned Hermit, etc.) image file size
Print works (Forbidden Scrollery, Wild and Horned Hermit, etc.) images are excessively large: visually grayscale images in 32-bit true color and even alpha?!?! That unnecessary bloating wastes the end users' bandwidth and times.
I will use Forbidden Scrollery Chapter 31 as an example.
I used ImageMagick with option
-alpha remove to remove alpha and TruePNG with option
/o4 to reduce PNG file size. This optimization is lossless; the image you see after is exactly the same as the image you see before, assuming none of the images beforehand used transparency.
|PNG color option and download||Size (B)||Ratio to original|
|Original (32-bit true color and alpha)||30 580 899||1|
|8-bit grayscale||20 815 072||0.681|
Optimizing all 24 images on a Intel Core i7-4710HQ and running 7 threads (optimizing 7 images at once) took 5 minutes. Just 5 minutes means 10 MB that no one: uploader, hoster, downloader, and reader, has to ever see again.
Forbidden Scrollery Chapter 30 images can be converted to 8-bit grayscale or 8-bit indexed (up to 28 or 256 colors represent the entire image) to reduce total file size as low as 40% of original but that process is lossy and lossless optimization is preferred. The scans should have never been done in true color in the first place.
Conclusion: What should those involved in producing the print works images do now?
- Scan in grayscale unless the page is actually in color.
- After editing, images need to be saved without alpha, unless transparency is needed.
- Optimize the image. I have created a Windows-only image-optimization starter pack that works with GIF, JPEG, and PNG. I implemented multi-threading into it so more than one image can be optimized at once.
- Thank you for the information and the useful tools! I've actually been worried about the image sizes, but honestly I don't know much about these things. And, frankly, I still don't because these tools make no effort whatsoever to be user friendly. That said, I'll try to figure them out. -Clarste (talk) 09:20, 15 December 2015 (UTC)
Compressing already-compressed files, including Thumbs.db, and using RAR
See screenshot of Forbidden Scrollery 35 archive: https://i.imgur.com/K1NNz9z.png
I do not know if the following was your intention, but you attempted to compress already-compressed files: using RAR to compress PNG, which is already DEFLATE-compressed. While compressing already-compressed files might decrease output file size (ex. the already-compressed file is not thoroughly compressed), the change is so small that it is a complete waste of CPU cycles. Luckily, WinRAR is smart enough not to do so, shown by the "m0" method, which indicates "store" as is.
Why is Thumbs.db included? It is an extra file that does not benefit Windows users who disable thumbnails and non-Windows users.
Finally, if none of RAR's compression is unused, why use RAR? Use ZIP, which has universal support, and is built-in into Windows (using the name "compressed folder"). If compression is needed, why use RAR in the first place when free, no license-nagging, and superior (in output file size in most cases*) 7-Zip exists? If you plan to use 7-Zip in the future to distribute translations, set "Archive format" to "zip", and "Compression level" to "Store".
- The simple answer is because I am just rightclicking on the folder and have winrar installed already. Thumbs.db is something that's been added to the folder automatically ever since I updated to Windows 10, and it automatically recreates itself when deleted so getting it out of the folder is more trouble than it's worth. Honestly, I don't even care about these archives, since I expect people to read the comics on batoto. I'm only adding them at all because people were bugging me, so I'm certainly not going to spend any extra time optimizing the process. So... not gonna change anything.