If you are talking the green flash before actual presentation of images, I don't think that is of major concern.
That's just the software behind rendering the image taking a moment to render.
If it remains green even with an at resolution copy of the image, then I'd be more concerned.
Thumbnails are approximate filled in copies of images. And especially high resolution thumb nails that have been shrunk to fit a certain resolution will have to omit pixels that make the whole image. Part of a problem of displaying UltraHD images on an HD display at less than optimum resolution.
To test the theory, get the full resolution of the image saved to your desktop, and use http://www.lemkesoft.com/ GraphicConverter to open the file. If at 100% it shows no artifacts it is the approximation that is causing the image problems.