Add command for regenerating pictures

[amureki]

Hey Johannes,

thanks again for the lib!

In my use case, I had my async worker failed several times due to the memory issues when migrating via AlterPictureField. As a recovery solution, I was following the steps that are done in the migration and ran the following script on a bigger server premises:

for obj in MyModel.objects.exclude(image='').iterator():
    obj.image.update_all(
        from_aspect_ratios=PictureFieldFile.get_picture_files(
            file_name=obj.image.name,
            img_width=obj.image.width,
            img_height=obj.image.height,
            storage=obj.image.storage,
            field=obj.__class__._meta.get_field("image"),
        )
    )

I am proposing to add this as a management command to have a simpler way of recreating the thumbnails. Here is a draft, happy to finalize it, rework if needed and add tests, but only if you accept it. :)

Best, Rust

[codecov[bot]]

Codecov Report

Attention: 19 lines in your changes are missing coverage. Please review.

Comparison is base (33562b8) 100.00% compared to head (769bc50) 96.11%. Report is 2 commits behind head on main.

Files	Patch %	Lines
...ictures/management/commands/regenerate_pictures.py	0.00%	19 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##              main     #153      +/-   ##
===========================================
- Coverage   100.00%   96.11%   -3.89%     
===========================================
  Files           13       14       +1     
  Lines          459      489      +30     
===========================================
+ Hits           459      470      +11     
- Misses           0       19      +19     

Flag	Coverage Δ
celery	79.14% <0.00%> (-5.18%)	:arrow_down:
cleanup	79.75% <0.00%> (-5.22%)	:arrow_down:
dj4.1	79.75% <0.00%> (-5.22%)	:arrow_down:
dj4.2	79.75% <0.00%> (-5.22%)	:arrow_down:
django-rq	79.14% <0.00%> (-5.18%)	:arrow_down:
dramatiq	79.14% <0.00%> (-5.18%)	:arrow_down:
drf	89.36% <0.00%> (-3.45%)	:arrow_down:
macos-latest	79.95% <0.00%> (-5.23%)	:arrow_down:
py3.10	79.75% <0.00%> (-5.22%)	:arrow_down:
py3.12	79.75% <0.00%> (-5.22%)	:arrow_down:
py3.8	79.75% <0.00%> (-5.22%)	:arrow_down:
py3.9	79.75% <0.00%> (-5.22%)	:arrow_down:
ubuntu-latest	79.75% <0.00%> (-5.22%)	:arrow_down:
windows-latest	70.14% <0.00%> (-6.90%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[codingjoe]

@amureki you should check the migration implementation. You don't need to reinvent the wheel here. If said wheel, is a hypersphere ;)

[codingjoe]

Since I didn't see much activity here @amureki I will close this PR. Feel free to pick it up anytime.