This happens on 5.5.1-nightly-15
I have the same issue on 5.5.0 by placing an image on a standard service.
The demo:
ferdi-2020-05-29_10.19.55.mp4.zip
The custom icon:

Same for me and can't get the original back as well
same here, tried png in different sizes but no luck
I am on 5.5.0 (Windows 10) and I have the same problem when placing an image to a custom website. I tried png (with transparency) and jpgs in different sizes.
Same problem. I can't set a custom icon for any service. Neither for custom websites, nor for implemented services. (5.5.0 on linux)
EDIT: Now after restarting the icons are just completely broken. All services where I to tried modify the icon have now no icon anymore... .
Please fix.
Same for me: All services where I to tried modify the icon have now no icon anymore after a restart.
Please tag this as a bug.
I believe this is duplicate of this issue https://github.com/getferdi/ferdi/issues/595 no news there either though.
I've solved it like this.
Same issue here, on 5.5.0 for windows and I can't get a custom icon for any default services.
I've tried both PNG and JPG, changing the icon size, etc.
I dug into this a little and it appears to be caused by a mismatch between what the "Save Service" PUT call sends from the client and what the server expects. If I set a custom icon, then the body of the PUT call is the icon data and nothing else, which returns a 400 error (NB this error is not reported to the user, it is only visible in the network tab of the developer tools). If I edit any of the other fields, as well as changing the icon, the icon is never sent.
Try 5.6.0-beta.2 per https://github.com/getferdi/ferdi/issues/595#issuecomment-648420560. That fixed the issue for me too.
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This is still an issue afaik ? at least on 5.5.0
Yes, having the same issue on Version 5.5.0 (5.5.0.2116)
Most helpful comment
I've solved it like this.
https://github.com/agichim/ferdi-recipe-custom-website