Can I use azure Bing Search resource with managed identity authentication?

@Ameer Muslih Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

Image Search API v7 REST API reference article clearly mentions that the Ocp-Apim-Subscription-Key is a Required field. So if this auth header is not specified, you cannot invoke the bing image search REST API.

Also refer the bing search docs which mentions about the required field Ocp-Apim-Subscription-Key. More info here.

On a side note:

Bing Search APIs are moving from Cognitive Services to Bing Search Services. Starting October 30, 2020, any new instances of Bing Search need to be provisioned following the process documented here. Bing Search APIs provisioned using Cognitive Services will be supported for the next three years or until the end of your Enterprise Agreement, whichever happens first. For migration instructions, see Bing Search Services.

Hope this helps. If you have any follow-up questions, please let me know. I would be happy to help. ** Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.