@Tseng, Venson This is a broad question with no one answer and would depend on many factors like tech stack, scale, etc. But I will try to provide an Azure specific answer with options to various components involved in an application like this.
Firstly, you will need to post your service somewhere. Some options here would be Azure App Service, Azure Functions, and Azure Container Apps. For the first and last options, you are free to choose any language/framework you are most familiar with.
Then you need one place to store non-files, so a database like Azure CosmosDB or one of the Azure Database offerings like PostgreSQL. You could even use something like Azure Table within a Storage Account if you'd like to keep costs low for a small project.
Finally, for the pictures themselves (or any files), you would use Azure Blob Storage which is designed to store/retrieve any file at scale. Typically, you would upload a file here and link to it in your database entries.
PS: If you open to it, explore Azure Functions which allows you to use bindings to quickly integrate these services together without writing a lot of code.