Hi. The app won't import pictures within Excel. Excel will only hold the picture file name.
You might want to watch the video on importing pictures using Excel and Dropbox. Even it you won't be using Dropbox, I think it's still worth watching. Instead of using Dropbox, you can upload text + picture files to my website for transfer when using text + media from your computer. (No need for any of this when creating flashcards in the app.)
https://youtu.be/cc-S9pH326AThe picture name you mentioned is the format the app uses for naming pictures added directly in the app.
If you want to share, one easy way is to export to "App Server". You'll give it a "deck code". Use a deck code that no one else will use. Make sure you export media also (using toggle). You can then share the "deck code" with classmates and they can download by tapping +, Private Deck, and using your deck code. Uploading to the App Server is intended for temporary storage space only. I'll delete files after about 3 weeks after last upload. You can re-upload every 3 weeks if you need to keep it fresh.
Or you can export to "shared library" if you want permanent storage, but you'll need to create an account to upload and users will need to search the shared library to find (you must make set public for them to find without creating their own account).
I don't have an export format yet that includes pictures that you can email people. This is something on my todo list. But one of the above options should work well. If you need more guidance or have concerns, let me know.