I moved my photo library to a separate SD card. In Finder there is now a Photo Library on the SD with 37Gb of data, and no Photo Library on the HD. However the System Info shows the HD is full with 39Gb of photos still taking up space. Why? What can I do?
MacBook Air 13″, macOS 10.15
You should reindex your hard drive for Spotlight: How to rebuild the Spotlight index on your Mac - Apple Support and get the library off the SD card an onto an external HD.
An SD card is not a suitable location for a Library. They are simply just not robust enough. Get an external disk or SSD and use that.
As for the space reported on the System Info. That "feature" is somewhat eccentric. Try rebuild your Spotlight index.
I don't know that you can format it correctly, either.
I have one formatted Mac OS Extended (Journaled), done with Disk Utility ages ago. I used it for storing books and pdfs.
OK, we don't know if the OP reformatted, though. That is kinda moot at this point.
Problems with photo storage
