GUI: Rescue if image size does not match experiment type or loader parameters
Currently, in case of such mismatch (e.g. BioDiff5000 data loaded as BioDiff2500), a std::runtime_error is thrown, with a message like "data file /local/testdata/BioDiff/Strep/p15843_00027666.tiff is not of the expected size: expected 4500000 bytes but found 18000000"