Thumbnail

In general, a thumbnail is a very small or concise description, representation or summary. In Bloom, thumbnails are used to show the front cover of the book. Bloom automatically creates thumbnails based on the front cover image of your book.

Here are things you can do with a thumbnail:

• In the Collections tab, you can update or rename it.

• In the Publish tab, choose a thumbnail color when you send your book to the Bloom Reader app.

• Create a custom thumbnail for an epub. It can include a title and subtitle that overlays a picture.

Do these steps:

1. Create a custom thumbnail with the largest dimension of at least 256 pixels. 
   Some might start with 1200 x 700 pixels. Bloom will reduce it so the largest dimension is 256 pixels.

2. Save that file with this exact name: epub-thumbnail.png.

3. Copy this custom thumbnail to the folder for the book.

Tip

Here are recommendations to consider for optimal images for an epub.

• Accepted formats: JPG, JPEG, PNG

• Recommended size: Smaller than 1 MB

• Ideal dimensions for mobile devices:

  • Aspect ratio of 1:1 whenever possible (square images)

  • Aspect ratio of 4:5 for portrait-orientated images

  • Aspect ratio of 4:3 for landscape-oriented images

• Amazon:

  • Minimum dimensions of 2560 pixels (height) x 1600 pixels (width) and a quality of 300 dpi for book cover images.

• Orientation for book cover images:

  • Cover images work best in portrait orientation, not landscape. This way, they suit the screen size of most e-reading devices.

• See Also: Add custom thumbnail for Bloom Library.

Related Topics

Concepts overview

Rename a book thumbnail

Show in File Explorer