[Updated 2023: Removing a star]

In addition to all the issues mentioned earlier, I've found that Download All Images does not download "blob" URL images. That means it does not work on many sites, such as the tiled images when zooming in on https://artsandculture.google.com/asset/el-si-pronuncian-y-la-mano-alargan-al-primero-que-llega-they-say-yes-and-give-their-hand-to-the-first-comer/NAHi_9r0H5PfJw .

For now, I am using the "Search by Image" extension to download blob images, but it can only do one image at a time. I hope that Download All Images will eventually add support for blobs.

[Original review from 2018 below]

Worked for Firefox (Adblock Browser) on Android, but was extremely clunky. All the unnecessary options should be hidden by default. The UI elements, like checkboxes should be bigger. The progress bar that says "saving" should be renamed "retrieving" as it doesn't actually save until you scroll down to the bottom of the panel and click "save". The Gallery should let you select images by clicking on them instead of a tiny checkbox. Gallery ought to be the default view.

In the end, this did work. I was able to retrieve an image that Google Books wasn't letting me get a context menu to save. However, it would have been easier to just use the save media option from Firefox's built-in Page Info (control-I) on a desktop than to struggle with this extension.