We have a size limit to uploading photos.
Because too big photos will slowly be loading on your ebay listing.
First way (recommend because is fast)
If you use Windows, we recommend installing PowerToys.
With PowerToys you can simply resize your photos by clicking the right mouse button on your photo and clicking resize.
Also, if you want to compress your photos without losing quality we recommend go to https://tinypng.com/ and compress (after this your photos also will less weigh).
Second way (good but slower)
An alternative way to resize is to go to http://www.simpleimageresizer.com/ and resize.
Next if you want you can go to https://tinypng.com/ and compress.
Third way (not recommend)
You can also upload photos to https://imgbb.com/ and paste the photo URL to the template in herolister
*but remember using free hosting image is not a good idea because your photos can disappear and you will not be informed about it
Fourth way (also good)
Also, you can use ebay hosting.
In 7:25 min you can see how to get a link to your eBay image:
So first you must add a listing with no template and upload photos to eBay, next you need to add these links to in template generate form and revise your listing by adding template code.
The best idea if you do photos by phone on camera please not set maximum resolution for example 4k (it’s not needed, the picture will be showing good), please use smaller resolution and quality.