Print what package should be installed when suitable writer is missing

[holgerroth]

Is your feature request related to a problem? Please describe.
I used SaveImage(..., output_ext=".png") but got this error message

monai.utils.module.OptionalImportError: No ImageWriter backend found for png.

This was after pip install monai in a clean environment.

Describe the solution you'd like
It would be great if the error message would include a description of how to fix the issue, e..g. "Please install pillow". Initially I installed simpleitk which also didn't have the png writer apparently, and I got the same error.

Describe alternatives you've considered
n/a

Additional context
Happened with monai==1.3.2

[holgerroth]

Same would apply for LoadImage and image readers for different formats

[Matteoilgiaco]

Hi, can i work on this issue?
I'm a beginner and i'm a self learner.

[holgerroth]

Hi @Matteoilgiaco , that would be great! Thanks for your interest in contributing to MONAI.

[iloveme81189-del]

Can i work on this issue. if the issue resolved can i add on my resume as contribution

[holgerroth]

@iloveme81189-del. Please coordinate with @Matteoilgiaco. Maybe you two can collaborate on this task?

[songhahaha66]

Hi, I’ve submitted a fix for this issue in PR #8625. The PR adds a clearer error message when SaveImage can’t find a suitable writer and points users to the package they need to install (e.g. Pillow). Please take a look when you have a moment.