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user/howto/specify-unlisted-image.md

@@ -1,4 +1,4 @@
-# Specify your own custom image for the software environment
+# Starting and customizing the software environment of a user server
 
 To start a server on the Hub, you need to go to the hub's home page, then click on the `Start My server button`.
 
@@ -26,8 +26,42 @@ The image above represents a `Server Options` page example, where you can choose
 - either a `"CPU only"` or a `"GPU"` **profile**
 - and for each profile, you can select from a list of pre-configured **options**.
   The options are:
-   - the docker `Image` that defines the software environment
+   - the docker `Image`, where you can choose from a list of pre-configured choices which image to use for the software environment
    - the `Node share` which represents the hardware resources available on the server. 
 
-### The "Other" option
+### The "Other" choice
 
+If it was enabled, in the dropdown list of pre-configured choices of an option, there might be an entry called `Other`.
+
+```{figure} ../../images/other-choice.png
+:alt: The "Other" choice
+```
+
+Selecting this choice, will allow you to input a free-form text value for that particular option, other than the pre-configured choices.
+
+
+## Specify your own image for the software environment
+
+```{important}
+Some important takeaways from previous section, that are relevant for the software environment customization.
+
+1. The software environment that runs on a user server is defined by a docker image. By using a docker image, your are enabled to reproduce your work on other machines more easily.
+
+2. The docker image of a user server can be:
+
+- pre-defined by hub admins
+- a list of choices that you can select from
+- a special `Other` choice that enables you to input your own custom option choice
+```
+
+The special `Other` choice of the `Image` option allows you to specify your own image for the software environment, in the form of `docker_registry/organization/image_name:image_version`.
+
+As an example, we can get the 2023.09.11 version of the pangeo notebook (that's not in the list of pre-configred choices) to run on a server with ~16GB of memory and ~2CPU (that's not the default node share) by:
+1. selecting the `CPU only` profile
+2. selecting the `Other` choice of the `Image` option (because 2023.09.11 version of the pangeo notebook is not available in the pre-configured list)
+3. pasting `quay.io/pangeo/pangeo-notebook:2023.09.11` in the input field that appeared
+4. selecting the pre-configured choice of `~16GB, ~2CPU` of the `Node Share` option
+5. clicking the `Start` button
+
+```{image} ../../images/new-server-custom-image.gif
+```