[Grazester]

There are libraries for converting HTML to PNG. Why would you need the frontend for anything?

Grab the users' achievement from the database(I could only assume user data is stored here). Format it however you want it to look in an HTML file then convert said HTML to a PNG. Its dead simple.

I did the equivalent but with PDF's for customer bills for a past job.

[Fruzenshtein]

the main point here — I can not find any good lib with good community on GitHub I know there is html2image-java, but it's not maintained for a while :(