Extend report documentation (#318)

* Small updates for reporting docs

* Fix navbar

* Add "media" link in navbar

* Extend documentation for reporting features and tags

docs/report/media.md

@@ -2,9 +2,13 @@
 title: Using media files
 ---
 
-## Images
+## Media Files
 
-To load images into the reports/labels the report helper must be loaded in the template. 
+*Media files* are any files uploaded to the InvenTree server by the user. These are stored under the `/media/` directory and can be accessed for use in custom reports or labels.
+
+**Load Report Functions**
+
+To load images into the reports/labels the report helper functions must first be loaded in the template:
 
 ```html
 {% raw %}
@@ -13,9 +17,79 @@ To load images into the reports/labels the report helper must be loaded in the t
 {% endraw %}
 ```
 
-### Assets
+### Uploaded Images
 
-You can add images to the reports and labels by using the asset template tag:
+You can access an uploaded image file if you know the *path* of the image, relative to the top-level `/media/` directory. To load the image into a report, use the `{% raw %}{% uploaded_image ... %}{% endraw %}` tag:
+
+```html
+{% raw %}
+<!-- Load the report helper functions -->
+{% load report %}
+<img src='{% uploaded_image "subdir/my_image.png" %}'/>
+{% endraw %}
+```
+
+!!! info "Missing Image"
+    If the supplied image filename does not exist, it will be replaced with a placeholder image file
+
+!!! warning "Invalid Image"
+    If the supplied file is not a valid image, it will be replaced with a placeholder image file
+
+### Part images
+
+A shortcut function is provided for rendering an image associated with a Part instance. You can render the image of the part using the `{% raw %}{% part_image ... %}{% endraw %}` template tag:
+
+```html
+{% raw %}
+<!-- Load the report helper functions -->
+{% load report %}
+<img src='{% part_image part %}'/>
+{% endraw %}
+```
+
+### Company Images
+
+A shortcut function is provided for rendering an image associated with a Company instance. You can render the image of the company using the `{% raw %}{% company_image ... %}{% endraw %}` template tag:
+
+```html
+{% raw %}
+<!-- Load the report helper functions -->
+{% load report %}
+<img src='{% company_image company %}'/>
+{% endraw %}
+```
+
+## InvenTree Logo
+
+A template tag is provided to load the InvenTree logo image into a report. You can render the logo using the `{% raw %}{% logo_image %}{% endraw %}` tag:
+
+```html
+{% raw %}
+{% load report %}
+<img src='{% logo_image %}'/>
+{% endraw %}
+```
+
+### Custom Logo
+
+If the system administrator has enabled a [custom logo](../start/config.md#customisation-options), then this logo will be used instead of the base InvenTree logo.
+
+This is a useful way to get a custom company logo into your reports.
+
+If you have a custom logo, but explicitly wish to load the InvenTree logo itself, add `custom=False` to the tag:
+
+```html
+{% raw %}
+{% load report %}
+<img src='{% logo_image custom=False %}'/>
+{% endraw %}
+```
+
+## Report Assets
+
+[Report Assets](./report.md#report-assets) are files specifically uploaded by the user for inclusion in generated reports and labels.
+
+You can add asset images to the reports and labels by using the `{% raw %}{% asset ... %}{% endraw %}` template tag:
 
 ```html
 {% raw %}
@@ -25,17 +99,3 @@ You can add images to the reports and labels by using the asset template tag:
 {% endraw %}
 ```
 
-!!! info "Assets location"
-    You need to place your asset images to the report/assets directory in the [data directory](../start/docker_dev.md/#data-directory)
-
-### Part images
-
-You can render the images of the parts using the part_image template tag:
-
-```html
-{% raw %}
-<!-- Load the report helper functions -->
-{% load report %}
-<img src='{% part_image part %}'/>
-{% endraw %}
-```