Fix OpenCV warning: "imwrite_ An unsupported key(1) was specified and has been ignored."

[s-trinh]

Currently when doing:

  vpImage<unsigned char> I_save(50, 50);
  vpImageIo::write(I_save, "save_png.png");
  vpImage<vpRGBa> I_save_color(50, 50);
  vpImageIo::write(I_save, "save_color_png.png");

OpenCV prints the following warning:

[ WARN:0@0.035] global loadsave.cpp:1140 imwrite_ An unsupported key(1) was specified and has been ignored.

Only when saving a jpeg image the "cv::IMWRITE_JPEG_QUALITY" flag must be passed to cv::imwrite().

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.68%. Comparing base (392f312) to head (b03c98f).
⚠️ Report is 8 commits behind head on master.

Files with missing lines	Patch %	Lines
modules/io/src/image/vpImageIo.cpp	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1917      +/-   ##
==========================================
- Coverage   48.73%   48.68%   -0.06%     
==========================================
  Files         532      532              
  Lines       69293    69293              
  Branches    32403    32403              
==========================================
- Hits        33770    33735      -35     
+ Misses      24977    24976       -1     
- Partials    10546    10582      +36     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.