[BUG] Wrong image is being used for exit transition when viewing images

[K1rakishou]

STR:

• Start downloading a thread.
• Wait until all images are downloaded (it's better to choose a thread with few images).
• Open an image.
• Swipe forward couple of image.
• Press back/swipe-to-close.

The first clicked image will flash for an instant before being replaced with the one that should be actually used for exit transition.

Apparently it happens after calling callback.setPreviewVisibility(true); which means previewImage has the wrong image, so it flickers for an instant before getting replaced with an image that we open in startPreviewOutTransition. When viewing images in regular threads everything works as expected.

[Adamantcheese]

This is just a regular old bug, as it happens in live threads as well.