Often the size of a ePUB is not the biggest issue. Still, usually the size can be reduced and as this program helps with that. Images usually contain unnecessary information that has nothing to do with the image and can be removed. When fonts are included in the ePUB, they can be subsetted and thus smaller. Many characters in fonts will not be used. Out with them! Finally, also the compression level of the ePUB can usually be enlarged (depending on the source)
So, in summary, the following things will be adjusted:
- Images reduces (JPG / PNG / GIF)
- Reduce fonts by removing unused glyphs
- better compression
The usage is simple. Either via the command line or just drag an ePUB on the icon of the program.
The program can be downloaded here: ePUBOptimizer1.12-setup.msi
This program also works with Mono on Linux and OSX.
There is also a Sigil plugin to use this program from Sigil. Program is included. Sigil version 0.8.2 or higher required: ePUBOptimizer plugin (versie 0.7.3).