@crossingthethreshold Thanks for sharing. Both Shortcuts worked for me on iOS 16.1.1. Hard to tell why they are not on your device.
Regarding privacy and permission, the Shortcuts need access to your Photo library and make network requests to micro.blog. So make sure that's the case by editing the Shortcut, hitting the ℹ️ followed by Privacy.
You can also try running the Shortcuts in editing mode. Sometimes that gives a clue as to where things go wrong.
Ensure the file you are uploading is a JPEG or PNG (not a HEIC). Also note that if you have more than one blog, the uploads might end up on one you're not expecting it to. (The last one you selected in the web interface.)
As a last resort, try removing and re-installing the Shortcuts.
@pratik is right that it's possible to design Shortcuts that only work on one platform or the other. But that's not true for the two Shortcuts you've shared. They work fine on both macOS and iOS.