Picture canvas

The Picture canvas holds an image.

Images are stored content-addressed in the notebook’s blob store, so the same image used on ten pages is stored once, and the store is refcounted so removing one use does not delete data another page still needs.

Cropping

Select the canvas and press Enter to move into crop mode, where the crop region can be adjusted from the keyboard. Escape leaves it.

Hotspots

Regions of a picture can be made clickable and given a link target — another page in this notebook, a page in another notebook, or a web address. A diagram becomes navigable: click the component and land on the page describing it.

Hotspot links go through the same link safety checks as any other link.

Captions

There is no caption field on the Picture canvas. A caption is a transparent Rich Text canvas grouped with the picture, which means a caption can be formatted, can contain a link, and can hold a citation — none of which a plain-text caption field would allow.

Embedded or referenced

A picture can hold its image data inside the notebook or reference it by location. Embedded is the portable choice: the notebook carries the image with it. Referenced avoids duplicating something large that already lives elsewhere, at the cost of the notebook no longer being self-contained.