In image occlusion, you generate flashcards from an image by hiding parts of it behind an opaque box on the front side, then revealing the hidden portion on the back side. It's like cloze deletion, but for images.

Image occlusion can be useful for any subject, but is especially helpful for visual-heavy topics like anatomy, chemistry, data science, or geography.

Before creating an image occlusion card, you'll need to add an image to your notes. Or, if you have the URL of the image handy, you can use /ioc (insert image occlusion) to add the image and start an image occlusion in one step.

Otherwise, Ctrl+click on the image you'd like to create cards for (Cmd+click on a Mac), or click the … in the upper-right corner of the image and select Generate Image Occlusion Cards.

This opens the image in a window where you can begin selecting what parts of the image you want to occlude. Click and drag to cover the area you want to test yourself on. You can occlude any rectangular area you want, and add as many different occlusions as you want.

By default, each occluded area generates its own card, but you can merge occlusions so that multiple areas will be covered on the same card. The large letters indicate which occlusions go together; each letter corresponds to a single card that will be generated.

To merge, hold Shift or Ctrl and click on as many sections as you like, then click Merge at the bottom.

If you change your mind, you can split one or more merged occlusions into their own cards by selecting them and clicking Split at the bottom.

To double-check that you've created cards the way you want to, select Preview Cards in the lower-right, which will show each card as it will appear when you practice it in the flashcard queue.

By default, everything is shown on the front side of each card except the specific occlusions that are part of that card. If you want to always hide all occluded portions on every card, while indicating which ones specifically you're supposed to answer in this particular card, enable the Hide All, Test One checkbox under Preview Cards.

Charts, graphs, models, diagrams, and flow charts make excellent image occlusion material. If you don't have the right one, consider making your own and uploading it to RemNote!

Image occlusion cards are also a fast way to test yourself on the contents of tables you might find in a textbook or on a website: grab a screenshot of the table, paste it into RemNote, and then generate image occlusion cards.

Image occlusion is an easy way to study important equations in subjects like chemistry, physics, or math. Snip the equation you need, upload it as an image, and start occluding!

(Note that you can also type equations directly in RemNote. But the image occlusion method can come in handy if you don't want to retype a long, complex equation whose LaTeX source you lack.)