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Diagram cards

Updated on August 5, 2026

A diagram card lets you cover regions of an image and reveal them one by one during review. It's ideal for memorizing anatomical diagrams, concept maps, circuits, schemas, or any labeled image you need to recall.

Create a diagram card

Open a deck and press New Diagram Card. Before you can draw boxes you need to load an image.

Upload the image

There are two ways to load the image:

  • From your device — drag the file onto the upload area or click it to browse. Common image formats are accepted (PNG, JPG, WebP, and others).
  • From the clipboard — copy an image in any other app and paste with Ctrl+V while the modal is open.

Once the image is loaded, the box editor appears.

Draw boxes on the image

  1. Press Enable Drawing. The editor border turns blue to show that drawing mode is active.
  2. Click and drag on the image to draw a box. Each box receives a sequential number.
  3. Repeat for every region you want to cover.
  4. When you're done, press Disable Drawing to exit drawing mode.

To undo the last box, press Ctrl+Z (or Cmd+Z on Mac) while the modal is open.

Remove a box

Outside drawing mode, click any numbered box to delete it. The message at the bottom shows how many boxes exist and that you can click to remove one.

To delete all boxes at once, press Clear All.

Save the card

A diagram card can be saved when it has at least one image loaded and one box drawn. Press Create to save.

How it looks during review

When a diagram card appears in a review session, the image is shown with all boxes covered. EON reveals them one at a time, from top to bottom and left to right. Each time you advance, the next box disappears to expose the part of the image it was hiding.

Zoom

If the image is large, use the Zoom control in the top bar to get a closer look. You can adjust the zoom level with the slider that appears when zoom is active.

Frequently asked questions

Can I replace the image after saving the card? Yes. Open the card with Edit Card and upload a new image. Existing boxes are cleared because they are tied to positions on the previous image.

How many boxes can a card have? There is no fixed limit in the code. In practice, between 3 and 15 boxes works well for review.

Are boxes always revealed in the same order? EON sorts them from top to bottom and left to right (reading order). That order is applied in every session.

Can I add front or back text to a diagram card? No. Diagram cards do not have a front or back field; the image and the boxes are the entire content.

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