Yes, it is okay to use different output formats.
What @mengdahl is referring to is that it is best to use BEAM-DIMAP as long as you want to use it for another processing step. Of course GeoTiff, NetCDF and others also work, but you will experience less issues with BEAM-DIMAP. But if the output of the graph is the final output of your processing then it is totally fine to use the format you woulke to use.
The issue here is actually that the error message is shown at all. The product after BandSelect is not multi-size anymore accroding to the report of @lusk.
My question is, my do you need the BandSelect operation, @lusk.
You can select the band already in the Subset operation.
If I leave out the BandSelect and select only bands of the same resolution in the Subset operation, I get no error.
But this also works if I select bands of the same resolution in the BandSelect.
What’s noteworthy is that the graph is only validated when switching tabs, or adding a new operator or when clicking on run.
If a parameter is changed the validation is not started immediately.
But this is for good reason. The validation can take quite some time depending on the data and the graph. Doing it with every paramter change would slow down the work with the Graph Builder.
And switching from one tab to another lets the error message disapear, eventhough nothing has changed and the error still persists. This might have caused confusion on your side @lusk.
For me the conclusion is that the error reporting in the Graph Builder could be improved. But it is actually working as intended.