white veil on openGL

i’m a fresh new user of harmony. When i import any kind of image jpg or png etc. , the render in openGL mode display colors with a white veil on it et on the cursor pointer there is icon like “parking prohibition”

Thank you for your help.

Difficult to say without seeing what’s selected in the timeline.

Is there perhaps another layer of transparent white covering the picture layer at the same frame?
Did you turn on the onion skin feature? This can wash out the BG depending on the settings.
Does it correct itself if you turn off the light table?