Senly loads images through an image proxy so your IP address does not leak directly to the sender (anti-tracking).
The proxy allows images from almost every public sender (Gmail, Outlook, GitHub, Railway, Stripe, etc.). What is blocked:
- Private IP ranges (e.g. 192.168.x.x, 10.x.x.x) — would allow internal network sniffing.
- Loopback (127.0.0.1) — same reason.
- IP addresses without DNS — suspicious.
- URLs with embedded credentials — XSS risk.
Missing an image from a legitimate sender? Send the mail header to support and we can investigate the cause.