Quote:
Originally Posted by Trane
About half the images are photos (jpgs) from a variety of sources, so there is no one resolution, but I purposely sought out the highest quality images I could find for the subject needed. Using PS to change PPI to 300... most were 240PPI so not a big jump. Also making them a uniform 600px wide. And again, most were close to that. Then Save for Web to compress/strip metadata.
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What's the average size of those JPGs? Maybe the quality can be tweaked slightly lower, or color can be changed from 4:4:4 -> 4:2:2. Or if they are grayscale you could save as Grayscale JPG. All depends on the images.
Quote:
Originally Posted by Trane
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This is Amazon's Kindle Publishing Guidelines. This is what you should trust:
https://kindlegen.s3.amazonaws.com/A...Guidelines.pdf
The KDP section of the site you mentioned is more for non-technical Word users. It also has a lot of wrong/misleading/dumbed-down information in it.
There USED TO BE a very old Kindlegen bug that converted PNG Transparency -> black background. Then also used to be a problem where it was converting Transparent PNG -> JPG.
Those two bugs were fixed years ago though.
There was also another PNG Transparency bug in KindleGen a few years ago:
https://www.mobileread.com/forums/sh...85#post2635085
but I haven't retested that in a very long time. It only happened with only a very specific method of compression and turned the entire image black.
Personally, I would export the PNGs with transparency, then run ImageMagick to mass convert those -> white background. Non-Transparent PNGs allow you to get much smaller filesize (if this filesize is such a concern). And doing it that way allows you to easily drag/drop the Transparent PNGs in the future.
Quote:
Originally Posted by Trane
So the only way to preserve transparency is to use GIFF.... so all the time spent converting the PSDs over again into PNG was wasted (originally made GIFFs then read PNGs are superior), and now have to create all new GIFFs again and then replace them in Sigil... Again...  (Yes, I saved the original GIFFs but as I made the PNGs I added effects in PSD to each image that I want in the GIFFs, so...) |
GIFs are ancient. PNG is superior in every single way. I wrote a post about this in 2013:
https://www.mobileread.com/forums/sh...54#post2632254
and I also wrote another post why PNG is superior to JPG when dealing with "artificial" images:
https://www.mobileread.com/forums/sh...10#post3029910
Quote:
Originally Posted by Trane
The other half include transparency (just about all created in PS), so made those pngs. There is a nice little (free) plugin for Photoshop called SuperPNG. It does a great job of compressing/removing metadata.
Having tried a few compression/meta-stripping programs prior, I found the two methods above to give the best results, in my case, for my images. |
Personally I am still a fan of ScriptPNG (about a year ago he merged his ScriptJPG+ScriptPNG into another program called pingo):
https://css-ig.net/pingo
Others use OptiPNG or TruePNG or whatever other tools. I believe there was another topic where everyone discussed their favorite compression methods (I swear it was one posted by GrannyGrump, but I couldn't find it in a quick search).
Pingo is just easy drag/drop and typically gets you the highest compression without needing to tweak any variables.