You are using staging server - a separate instance of the ESP Component Registry that allows you to try distribution tools and processes without affecting the real registry.
# ESP-GMF-Image - [![Component Registry](https://components.espressif.com/components/espressif/esp_muxer/badge.svg)](https://components.espressif.com/components/espressif/esp_muxer)
idf.py add-dependency "jason-mao/gmf_image^0.0.2"