It's on PPC 32-bit that I see the problem. In fact, I can see multiple instances of JPEG entrypoints in e.g. Linux .so files as well, but maybe the dlopen implementation is sufficiently different to avoid any issues.
A quick fix that I found is to add RTLD_LOCAL in the call to dlopen() in dynamic_load.c:f_load_module() but Grubba advised against it because there's apparently some cross-dependencies among other image modules that would break.
I'm now investigating if there are any compile-time flags that can force the .so files to bind their external library references earlier instead of delaying them until runtime. No luck yet...