And guys, I'm bit embarrassed you guys are keep giving taunt item in .png format.
You should give taunt items in .gif format. I don't know which tool you're using, but please give the files in .gif format.
So, quick review for this:
[Files I needed for taunt itmes](1) Red
.gif, Blue
.gif --> For preview image, it takes so many times for me to turn your .png file to make .gif preview image. Therefore, please make Red.gif, Blue.gif which is your taunt item divided by each team. Size doesn't matter, but 64*64 is just perfect for me. You don't have to change it because its normal size is 64*64px. Its background color should be transparent because I have to use it for preview image.
(2) Taunt
.gif --> Your actual item, can be in any length. Also its background color can be whatever you want. For tip, transparent background can be a problem if added in-game, by making specific color(usually white or black) in your item transparent, it is GM's problem. For this reason, I recommend it to be any color that you didn't used for your item, like magenta, cyan, dark green or whatever because it is more safe.
(3) Thumbnail
.png --> Like all other items, taunt item also should include thumbnail image. Taunt thumbnail should be drawn in specific format.
4.
Now make a thumbnail image for web.
(1)Thumbnail must related to item you're making.
(2)You can choice whatever size for your thumbnail under(64*64). I strongly recommend (16*16), (32*32), (48*48), (64*64) because it looks good on web.
(3)If you're making Head/Torso/Leg/Weapon, your thumbnail should include only item image, not text or non-item related image.
However, you can include your own small watermark for your item thumbnail.
(4)If you're making other Taunt item, your thumbnail should be drawn on this:

With these colors

Sample output is this:

Gang-Star's thumbnail by DKn
[Why do I need gif format?]It's simple, because I don't know your taunt item's length.
As you may know, I don't restrict animation length of your taunt item. It can be short or long whatever you want, so I can't get length of your item automatically.
There're two main formats of image I use, .png and .gif
Here's api for adding sprite at runtime of gg2.
sprite_add(fname,imgnumb,removeback,smooth,xorig,yorig)
Adds the image stored in the file fname to the set of sprite resources. Many different image file types can be dealt with. When the image is not a gif image it can be a strip containing a number of subimages for the sprite next to each other. Use imgnumb to indicate their number (1 for a single image). For (animated) gif images, this argument is not used; the number of images in the gif file is used. removeback indicates whether to make all pixels with the background color (left-bottom pixel) transparent. smooth indicates whether to smooth the edges. xorig and yorig indicate the position of the origin in the sprite. The function returns the index of the new sprite that you can then use to draw it or to assign it to the variable sprite_index of an instance. When an error occurs -1 is returned.
As you can see,
When the image is not a gif image it can be a strip containing a number of subimages for the sprite next to each other., which means if I don't know actual animation length, I can't add it properly.
Actually, I know that there's other way for doing it. By just adding sprite and with its sprite width/64, we can actually get the length of animation, but it's too expensive procedure.
Therefore, please submit your taunt items in .gif format please.
[Other item types that use .gif format]Not only taunt, but also pet and death animation is also using .gif format.
As I mentioned above, reason is simple. Because I don't know exact animation length of your item.
So, your death animation item should be in .gif format.
Pet is little bit different. Pet can be either .png or .gif, but I can't accept .png sprite which has more than 10+ animation length.
It's because of method of adding pet sprite in my plugin, so if your pet item has more than or equals 10 animation length, please change it to .gif format and submit it.
So, please reupload Boomer(with spy drawn), flamefist, sparingsoul, and all S0lid's taunts in .gif format.