Adding type preservation to insert_image

[keykholt]

Description

This PR address issue 1440. At the start of the function, the dtype of the original data is stored. Before returning the modified image, the return value is cast back to the original dtype.

Fixes # 1440

Type of change

Please check all relevant options.

• Improvement (non-breaking)
• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Testing

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[lgtm-com]

This pull request introduces 12 alerts when merging 69a8d2b into 09e0e19 - view on LGTM.com

new alerts:

• 12 for Module is imported more than once

[beat-buesser]

closing and reopening to get tests started

[codecov-commenter]

Codecov Report

Merging #1441 (69a8d2b) into dev_1.9.0 (c114a49) will increase coverage by 0.55%.
The diff coverage is 100.00%.

@@              Coverage Diff              @@
##           dev_1.9.0    #1441      +/-   ##
=============================================
+ Coverage      89.85%   90.41%   +0.55%     
=============================================
  Files            237      237              
  Lines          19386    19387       +1     
  Branches        3438     3438              
=============================================
+ Hits           17420    17528     +108     
+ Misses          1172     1077      -95     
+ Partials         794      782      -12     

Impacted Files	Coverage Δ
...cks/poisoning/perturbations/image_perturbations.py	89.74% <100.00%> (+0.13%)	⬆️
art/attacks/evasion/boundary.py	92.72% <0.00%> (-1.22%)	⬇️
art/utils.py	90.92% <0.00%> (+16.28%)	⬆️
art/visualization.py	90.47% <0.00%> (+16.66%)	⬆️
art/data_generators.py	93.97% <0.00%> (+27.71%)	⬆️

[beat-buesser]

Hi @keykholt Looks good to me. Thank you very much!