TinyImage includes a Downsizer feature which lets you automatically resize (and lightly compress) any Figma image fills on your layers to their actual layer size. This is useful if you've originally imported high resolution images to your Figma file, but then shrunk the layer dimensions down to be much smaller (with the original large image file still being used).
One common case of this would be adding a large image from Unsplash (or another stock photo site/plugin), the resizing that layer to be used as a much smaller "card" or "avatar" image. This can cause the performance of your Figma file to slow down; so using something like this downsizer feature will help save file size and improve page performance in your Figma file.
Using the Downsizer feature to optimise image fills on your page
To get started with downsizing your Figma fills, open the Downsize tab in the TinyImage header.
The Downsizer scans every layer on the current Figma page for image fills. Use the checkboxes in TinyImage to choose which fills should be downsized, and click the refresh icon, labelled Rescan all fills on this page, whenever you need to rescan the page.
Selecting layers in Figma narrows the list when those layers match image fills that TinyImage has already loaded. TinyImage shows Showing selected layer fills while this filter is active. If the current selection has no matching fills, TinyImage keeps the full loaded list visible. Changing the selection does not rescan the page; use the refresh icon to load newly added fills.
Selecting the image fills to downsize
Once the image fills have loaded, you can select which you would like to downsize by checking or unchecking them in the list.
If you're unsure which fill relates to which layer, you can click on the Image icon button in the list, which will instantly zoom and scroll to that layer on your Figma page.
Downsize your fills
When you're happy with your fill selection, use the scale selector to choose the resolution that you would like your Figma image fills to be downsized to. By default this is set to @2x, which means your image fills will be proportionally downsized to be exactly twice the size of the Figma layer that they're being used in. You can select @1x to resize the image fills to the same size as their Figma layer, but it won't be as sharp as the @2x option.
When you're ready, click on the Downsize Figma Image Fills button to start the downsize process. TinyImage will automatically detect if an image needs to be downscaled or not; any that require downsizing will be resized (and lightly compressed), then automatically replaced in your Figma layers. Once every image has been processed, you'll be able to see the total amount of size you've saved in your Figma file.
Undoing image downsizing in Figma. If you've used the Downsizer function accidentally, or selected some image fills by mistake, you can use the normal Undo function in Figma to rollback the image fill updates to your original image fills. Alternatively, if you need to go further back, you can use the File -> Show Version History in Figma to roll-back your file to a previous version.