Add URI info

NEWS.md

@@ -47,6 +47,7 @@ sudo make install
 * Do dataset price returns zero or null [#15408](https://github.com/CartoDB/cartodb/pull/15408)
 * Fix ensuring uniqueness working with kuviz [#15417](https://github.com/CartoDB/cartodb/pull/15417)
 * Update CARTOframes onboarding [#15420](https://github.com/CartoDB/cartodb/pull/15420)
+* Update CartoCSS info about URI images [CartoDB/developers#651](https://github.com/CartoDB/developers/issues/651)
 
 4.32.0 (2019-12-27)
 -------------------

doc/developer-center/cartocss/01-properties.md

@@ -1445,6 +1445,8 @@ You can also apply simple math using float number values. For example:
 
 A uniform resource identifier (URI) is a string of characters used to identify the name of a resource, typically a path on your computer or an internet address. You can also apply a URL (as if using HTML), to define a URI image location.
 
+> In CARTO style code, only an URL to a publicly-available image can be used.
+
 {% highlight scss %}
 #markers {
   marker-file: url(http://com.cartodb.users-assets.production.s3.amazonaws.com/simpleicon/map43.svg);