As an aside - something that I thought would work but did not - several years ago Link gave the useful tip that the AC Figure Tool can be used to convert an image from one format to another. Just open an image in the Figure Tool Settings dialog and then, still in the dialog, use the "Save As" button to save in the new format.
Since the Figure Tool has a "Transparent" checkbox, which makes all pixels of the same color as the top left (as I recall) pixel transparent when the image is placed... I was hopeful that doing a Save As would save this transparency info to the reformatted image file - but alas it doesn't. So, have to stick with Photoshop or similar...
One of the forum moderators
AC 28 USA and earlier • macOS Sonoma 14.7.1, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB