For context: some spam and phishing attempts use remote images in messages that are tied to unique identifier URLs. In short, once your mail client loads the image from the remote URL (just like a webpage), the scammer knows that your particular email address works, and that you check your mail. It’s like flagging yourself in the spam world to say “please, sir, I want some more.”
To help protect yourself from these schemes, you can disable remote images in Mail for iOS (and Mac), then load images on a per-message basis when you trust the sender:
- go to Settings > Mail, Contacts, & Calendars
- scroll to the Mail section and disable “Load Remote Images” (pictured)
Now, when you open a message that contains remote images, you’ll see blank boxes where said images should be. If you trust the sender, you can scroll to the bottom of the message and tap the “Load All Images” button (pictured). As of this writing, there’s no way to load individual images; it’s all or nothing.