Hi, I'm working with images that were already exported from Spine and imported into Unity.
In order to create different arts but avoid new animations, I'm taking part of the textures into photoshop, edit them, and replaced them in Unity. But this cause a weird behavior on the edited textures, it has weird artifacts and the only way to fix it is by importing the new images that were edited in photoshop to spine and export the animation again.
There is anyway to fix this issue? Thank you!
It's probably because your atlas uses PMA images. Photoshop can't read or save PMA correctly. You probably will want to modify the images and pack them into a new atlas with PMA.
Even if you stop using PMA in your atlas, you still probably don't want to modify the images with Photoshop because it does not apply the bleed effect that Spine does to set colors on fully transparent pixels, which prevents artifacts with non-PMA rendering when images are filtered at runtime.
Hi Nate! Thank you for your quick response. Does it mean that there isn't a way to edit images with photoshop after they were exported from Spine?
You can edit the images, but as explained, Photoshop will wreck them. Other image editors may do better.
Did you export an atlas with PMA images? You can edit them, but Photoshop will show dark borders around the edges and wreck the PMA when you save.
Did you export an atlas with with bleed and without PMA? You can edit them, but Photoshop probably wrecks the colors of fully transparent pixels when you save, causing artifacts at runtime.
Did you export images that aren't in an atlas, like a PNG sequence? You can edit them just fine, they are normal images.
I use atlases and I tried different versions (with PMA, without PMA, with bleed..) and I see all the issues you mentioned above.
I understand, do you recommend any other specific image editor instead?
thank you!
Unfortunately I'm not sure what image editing software can handle PMA (or bleed). I'm a programmer so the artists try to keep me away from such things. 
If you saw the issue even without PMA, then maybe the issue was misdiagnosed. It may help if you show the artifacts you are seeing.
Editing the source images and repacking the atlas is still likely the best way.
denissehakim92 I think the content from 4:50 of the following video might be helpful. The chapter title is "5.Artifacts around attachments after editing textures using Image editors":
As explained in the video, GIMP allows you to preserve the color values of transparent pixels.
