Some applications (like acdsee v3.1) produce PNG files that can't be opened in Okular while gwenview, GIMP and ImageMagick is able to display them. For such files QImageReader returns false as a result of open operation while resulting QImage still gets a valid data. This patch soften image file open checks. Now file open error is not reported if resulting QImage is valid even if read function returned false.
A test png is attached.