The background is the bottom of the stack — everything else in
the cover designer sits on
top of it. You have five ways to set it.
The five choices
- Generate — describe the picture you want and let OutaStory
create it for you. - Plain colour — one flat colour across the whole cover. The
quietest option, and often the strongest one for text. - Gradient — a blend between two to four colour stops. Set
each stop's colour and let the designer blend them. - Upload — bring your own picture from your device.
- Keep — leave the cover the story already has and change only
the layers on top.
A design can hold only a limited number of AI-generated images, so
generation is not unlimited — the exact caps are in
Cover limits, versions and the OutaStory mark.
Uploading your own image
Uploads accept PNG, JPG and WebP, up to 5 MB.
Choose a picture that is at least as large as a cover slot, or it
will look soft when it is scaled up. Photographs with a calm area —
sky, wall, water, blur — give your title somewhere to sit.
The 5 to 10 MB trap
This one catches people out, so here it is plainly.
The check in your browser lets a file through if it is under 10
MB. The server then applies the real limit of 5 MB and refuses
anything bigger. All you see is the generic message "That image
couldn't be uploaded." — it does not say the file was too large.
So if an upload fails for no visible reason, check the file size
first. Anything between 5 and 10 MB will fail exactly this way.
How to shrink an image
Any of these usually gets a photo comfortably under 5 MB:
- Reduce the dimensions. A 6000-pixel-wide photo is far larger
than a cover ever needs. Resizing the long edge to around 2000
pixels typically cuts the file to a fraction. - Save as JPG instead of PNG. PNG is meant for flat graphics and
line art; for a photograph it can be several times bigger than a
JPG that looks the same. - Export at a lower quality setting. Most photo apps offer a
quality slider on export — around 80 % is usually indistinguishable
by eye and much smaller. - Re-export a screenshot. Screenshots are often saved as PNG and
are surprisingly heavy for what they show.
Then try the upload again. If it still fails and the file is well
under 5 MB, check that it really is a PNG, JPG or WebP — a renamed
file keeps its old contents, and formats such as HEIC, TIFF or SVG
are not accepted.
Choosing a background that works
Covers are seen small. Before you settle on one, step back from the
screen far enough that the cover is about the size of a thumbnail
and see whether it still reads. Busy backgrounds usually lose that
test; a single colour, a soft gradient or a photo with one calm
region usually wins it.
More on keeping the title readable is in
Text on your cover.