💡 Today I Learned

Adding a cover image to a gitbook

To include a cover image (used in the pdf and epub outputs)

Step 1: Create a file called "cover.jpg" with width 1800px and height 2360px, and place it in the root folder of your gitbook.

Step 2: There is no step 2.

(Assuming you are creating it with Paint.net, you'll no doubt make heavy use of layers, and keep the original .pdn file. Inkscape also a distinct possibility.)

To auto generate a cover

Tl;dr; Never do this.

Add the autocover plugin

npm install gitbook-plugin-autocover

This failed with:

gyp ERR! configure error
gyp ERR! stack Error: Can't find Python executable "python", you can set the PYTHON env variable.

Because:

Some npm plugins need node-gyp to be installed. However, node-gyp has it's own dependencies (from the github page)
—http://stackoverflow.com/a/21366601/49

in book.json, include title, author, plugins and `pluginsConfig', e.g.

{
    "title": "Today I Learned",
    "author": "Leon Bambrick",
    "plugins": ["autocover"],
    "pluginsConfig": {
        "autocover": {
          "font": {
                "size": null,
                "family": "Impact",
                "color": "#FFF"
            },
            "size": {
                "w": 1800,
                "h": 2360
            },
            "background": {
                "color": "#09F"
            }
        }
    }
}

run gitbook install

Anyway if you're only doing 1 or 2 books, it is not burdensome to create the cover yourself manually (or pay a professional!)

If you are bulk creating 1000's of books, I suggest writing your own program/script for generating the cover image, and never using auto cover.

Sources