I’ve managed to reach it merely by uploading two JPEG banners and avatars for two communities: [1] [2]
{"data":{"error":"rate_limit_error"},"state":"success"}
Considering that the image upload previewer isn’t 1:1 with what the website sees, and images cannot be repositioned after upload, this matters.
The image upload rate limit on lemmy.ml is currently set to 6 per 3,600 seconds (1 hour). I can’t tell how many you’ve uploaded, but you can by going to your profile and clicking “Uploads”.