I think I got that error if the thumbnail size is over 1MB.
Hi
Could you try to reduce the preview image quality to 640x480 with jpg formate?
I think I got that error if the thumbnail size is over 1MB.
Yes, related errors are always because of this.
The correct thing is to be below 1MB the thumbnail (JPG Mod).
I use Photoshop and when saving the image I only make a simple change when it exceeds 1MB.
I change the quality from 12 to 11.
I keep the image always in Full HD (1920x1080).
More if you prefer it decreases the resolution of the image.
Maybe you use Corel Draw, I believe you should have similar options when saving your file.
I used Corel a few years ago I don't remember the interface.
If I had it on the PC I would check the settings.
I hope it helped.
Thumbnail photo max only 1mb. 940kb and lower is best.
Oh yes, thanks a lot PigeonBB , MBO530 , Daniel F SilentStealth-TR .
I forgot to reduce the picture size. It's not nice to become old.
I laughed a lot when reading your comment.
Sometimes I also forget to pay attention to size. Seconds before sending the files I check if everything is correct. 
I believe it is the prey to send to Workshop. 
Yannick [FR] happens to all of us 
