Magento 2: jQuery: User Get Blank Image In Email

I’m using Magento 2.2.1, i have a issue to fix, i’m using drawpad jQuery but i’m stuck in it, there is a frontend page like this: enter image description here

Here user draw line where he wants to or mark the parts, and submit the request, but when he get email, sometimes in email user gets black image with marks of the user like this: enter image description here

And sometimes user get correct image like this: enter image description here

Please help me fixing this issue.