# Gallery with Rx.js Hi there! If you’re reading this I know you’ve already built some web applications and it went pretty well! You know how to store and display data. You know how to react to user events and communicate with servers. Even styling your applications gets easier every time you do it! Today we’ll dig deeper into managing user and server interaction. With Rx.js you’ll take control of time in your application. You’ll create Observables to easily merge, filter, and synchronize events happening in your application. Let’s go! By the end of that tutorial you will have the working photo gallery which allows you to upload your own photos and categorize them. The preview of final app is available [here](https://stackblitz.com/github/jonki/observable-gallery/tree/master/examples/3_05-add-photo-to-category/). PS. You may want to check RxJS documentation from time to time. Go for . may also be useful. Also library called Ramda is used here few times. In need of explanation go here: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://ng-girls.gitbook.io/todo-list-tutorial/more-workshops/hello.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.