(I tried inserting a picture of the Goblin Mech card right here but I keep getting image upload error messages, if anyone knows how to fix that please help)

I had this problem for ages. I eventually found out it was because you need to "link" and image rather than upload it. e.g. if you upload an image to a photo hosting site (such as photobucket), you can then provide a link from photobucket to you Hive article.

It is a real faff. I now mostly write my articles on Publish0x (https://www.publish0x.com?a=3YaO71Agax) as you can upload images to that site. I then use the image link from my Publish0x article on any of my Hive articles.

BTW - my experience on Splinterlands is very similar to yours. I have only been on for just under two weeks, and am getting c. 1-3 DEC per match so saving to buy cards is frustrating. I also complete a quest in about a day too.