Hi @joshw ,
Thanks for reaching out to us! We support a maximum file size of 40MB for images, so feel free to upload the same large, high-quality photos you're used to seeing on iFixit.
Based on your question, it sounds like your image might not meet Dozuki's minimum file size requirements. Guide images in Dozuki have a minimum requirement of 800px by 600px. If you receive an error message specifying resolution, you're most likely encountering a conflict with our minimum resolution requirement. I'd recommend double-checking your images to confirm their resolution. If your images meet our minimum requirements and don't exceed 40MB, please reach out to our support team at firstname.lastname@example.org. They'll be able to help with any technical issues on your Dozuki site.