fixed bug, I found that opencv always copy 32 bit bmp data as rgba(4 channels), but rgb data can set as 32 bit pre pixel too, so we need to check BI_RGB, I have added the test file test_32bit_rgb.bmp to opencv_extra repo.

Thank you for contribution!

As a bug fix this patch should go into 3.4 branch first.
We will merge changes from 3.4 into master regularly (weekly/bi-weekly).

Please:

• change "base" branch of this PR: master => 3.4 (use "Edit" button near PR title)
• rebase your commits from master onto 3.4 branch. For example:
  git rebase -i --onto upstream/3.4 upstream/master
  (check list of your commits, save and quit (Esc + "wq" + Enter)
  where upstream is configured by following this GitHub guide and fetched (git fetch upstream).
• push rebased commits into source branch of your fork (with --force option)

Note: no needs to re-open PR, apply changes "inplace".

Please rebase related opencv_extra PR too.

I have pushed my change to 3.4, please check, thank you!

wants to merge 2,475 commits

needs to force push to the branch 32bit_rgb

Thank you for update!

+78.4 KB testdata/highgui/readwrite/test_32bit_rgb.bmp

Could you please to put small image to opencv_extra? E.g. 16x16 or 64x64 pixels shuold be enough.

I pushed an image which is 48x48 pixels