Problems with gif previews

[jukajo]

Edit: Solved! Check out Yoyobuae's post right below this one for the solution.

Hello!

I am having trouble with gif previews in my gallery. While you have to upload an additional thumbnail when uploading gifs, said thumbnail is only used in the 'Lastest submissions' section on my front page (and I think in people's favorites, since it's the same kind of gallery) and even there only for the small previews. In all other places, a picture randomly created from the submission by the page itself is used.

Gifs only work as they should when watching gif submission is full view. Before clicking on full view, a preview is automatically created from the gif itself, which is completely random in size, clipping and animation frame used. This weird picture is what's used everywhere but at the aforementioned place to preview the gif, instead of the thumbnail which was created just for that purpose.

Here are pictures of what I mean:

The Latest Submissions section. As you'll see the small previews (thumbnails) are perfectly fine, but the large one is this weird random bit of the animation...

...that is the same as the standard size of the actual submission (which is not at all what it should look like.

Since the example above is not that bad, look what other gif previews in my gallery look like to get a better idea:

The picture on the top left and the one in the middle with just the white eyelids visible are the exact same size (500x500px), still they get completely different randomly chosen previews. The one on the left with the eye got this completely random tiny preview. which is just a small piece from the actual animation. And then comes the picture on the right which looks perfectly fine?!

I haven't done anything differently with these as far as I can tell and they were all made with the same program. If they were all square cutouts of the actual submission I'd get it, but this? This is just completely random. And I guess I don't have to tell anyone it looks completely awful

After finding out you can get rid of the weird scratchy white previews by turning off transparency when saving gifs, I'm hoping to find a solution for this, too. Is there a special way I have to save the gif to get a nice preview? I'm sure I'm not the only one who has this problem. If there's no solution, a fix would be greatly appreciated!

~jukajo

 

[Yoyobuae]

If I'm not mistaken, the preview is generated by extracting one frame from the animation. Problem is that in optimized GIFs not all frames are the same size as the full image, some frames could be a small square portion of the image (the parts that change) to make the final GIF smaller.

The way around it would be to force a full frame to be saved to the GIF file so it gets picked up by the preview generator. Not sure which frame is used, I think it's the last frame.

In GIMP you could set the disposal to "replace" for that frame, so a full frame is saved in the file. If you can't directly set the GIF disposal mode, then modify one or more pixel in two opposite corners of the image, effectively forcing a full frame to be encoded into the GIF (only a full square would include those changing pixels at the corners).

 

[jukajo]

@Yoyobuae You are my hero! It seems kind of obvious now you say it... yes, it's always just the part that changes that 's displayed as the preview. Makes sense that a gif would be saved like that. Putting two slightly different colored pixels in the corners on the very last frame does the trick and isn't visible to the naked eye. I use photoshop and I have no idea how I'd save 'full frame' gifs there, but for now this workaround will do. Thanks so much!