I tried to open several png files with I believe Impress and LO crashed. Now all those png files are called .~lock.“name of file”#
Lock files are small text files which indicate a file is open and should not be modified by another program until it has been closed by the first program. They are not your png files.
The png files should be still where they were stored originally, are they? Did you let LibreOffice try to recover the Impress file?
If you cannot see the original files, were they stored on a OneDrive folder? If OneDrive deleted the files while they were in use that could have caused the crash of LO. In which case look in OneDrive recycle bin.
Were the files stored on the same computer as the LibreOffice program you were working on? What operating system does it use? If it is Windows and you log in using a Microsoft account then OneDrive might be involved, of course so could hardware failure. Were the image files stored separately? Or just saved in the Impress file?
Can you open the Impress file with a zip program like 7zip and copy the images from there to a folder?
What happens if you use the operating file managers search function to search for files (anywhere on computer) named the same as the original png file?
No they are not where they were stored.
And YES I did let LO try to recover the files BUT it crashed/shut down
before any thing was recovered 
I don’t use OneDrive…
I also have LO install on Linux, would that help in unlocking ?
I have 111 graphic files that I made and are now locked
Sure hope you can help !
This isn’t an answer. Can you click on more below your answer and click on Repost as comment. Cheers, Al
First, you can delete all those lock files safely, as explained by Earnest Al, they are not the actual pics.
Have you dragged and dropped the pics to the presentation? Better avoid that. If you want to insert pics in a presentation, use the icon to add a picture or use the Insert > Image menu. Note that I get the lock file only if I drag and drop a pic in the start center, without any document opened, and it inserts the file in Draw.
This is rather weird because the lock file appears only in case the file is opened for edition.