Image size guidelines

[OvertureDesigns]

Hi all, 
Just wondering if there are any official Zazzle recommendations for image sizes when uploading designs. I do a lot of purchasing graphics for my designs and a lot of times the graphics are something like 4,000 x 4,000 which feels excessive for something like a coffee mug haha. I just feel bad for taking up so much of Zazzle's server space and am also curious if Zazzle has any kind of document or guideline on file size for say a keychain vs a cornhole set.
Thanks!

[Cat]

In theory there are "guide files" for some of the products, but I don't really understand how to use them. Creating and Uploading Images to Zazzle – Zazzle Help Center

My strategy is to upload the biggest image possible because that way if the customer transfers the design to a bigger product they're less likely to encounter a problem (shower curtains and area rugs notwithstanding!) The only time it's caused a problem for me was when I grouped and tiled a bunch of fairly large images - it ended up creating a product that had a SUPER slow response time when the customer tries to edit it.

[Windy]

The only thing I know about this, is that often when I try to upload a large image, it won't upload, and no detailed message is given as to why. I can always make the image upload if I reduce the image below a certain threshold.  I agree with @Cat that you want an image large enough to make transfers possible. 

Once you have uploaded and used an image, you can delete it from your image library if you have no plans to use that image again.

[Cat]

@Windy Thanks for the tip on deleting stuff once the product is made - I didn't realize you could do that! I wonder if it works the same way for covers. I've got a LOT of stuff hanging out in My Images! 

In terms of size, I've never had that problem, but I don't generally use PNGs which keeps the file size down. Most of the stuff I do is either watercolors or line art. Since watercolors don't really need sharp lines, I use jpg, and for line art I try to stick with svg. As always, YMMV!

[Windy]

Yes I delete all my covers a day or two after I add them to my product.