[ECR] [request]: Ability To Prioritize Images To Scan

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**Tell us about your request**

_This request was submitted on behalf of a customer_

The ability to prioritize images to scan when using the image scanning feature.

**Which service(s) is this request for?**
ECR

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
To check important images in the environment first to make sure that they do not contain vulnerabilities.

**Are you currently working around this issue?**
No.

**Additional context**
N/A

**Attachments**
N/A

Start by reviewing how ECR image scanning currently selects images and how important images are identified in the environment. Define the prioritization behavior and its scope before implementation; done means users can cause important images to be scanned before others and verify that ordering. The issue names no repository files or tests, so the implementation entry point is not specified.

Written by the indexing model from the issue text.