What Image Formats Work?

[storax]

I’m making my first eBook as a favor to the author. The project was put on hold for while the author took the book back for another ‘final’ edit. Now, after a rather long hiatus, I find myself confused about what image formats work.

The author wants two small woodcut-like images, one that’s used as the writer’s ‘glyph’ and another for the title page that echoes the main element of the cover art. If I were making a website, I’d simply use transparent .png or .gif files.

But I’m not, of course.

My hazy recollection (I should have kept better notes!) is this:

amzn-mobi:

• png files are converted to .gifs. if less than 128k
• .png files are converted to .jpg format if over 128k
• Transparency is not supported

Amzn-kf8

• .png files work, but transparency is not supported
• .gifs work, but transparency is not supported, at least in night and sepia modes.

EPUB (ADE reader)

• .png files work, and transparency is supported
• .gif files work, and transparency is supported

My idea (approved by the author) is to make two image files for each image: one of the simple glyph and one with the same glyph in a woodcut-ish border. By that I mean the image will include a frame close to the edge; the CSS will still have border: 0

For EPUB and amzn-mobi I’ll show the naked glyph. White on off-white is close enough for the e-ink Kindles, or at least that’s my thinking.

For amzn-kf8 I’ll show the glyph with the border, which should take care of the horrible uglies in night mode on a Kindle Fire.

Am I close to a reasonable solution?