Hello, The following has been mentioned in the documentation regarding the algorithm used for selecting the primary node type of the file uploaded - "If a @TypeHint suffixed parameter is not present or the value does not denote an existing non-mixin node type, the node will be created as an nt:file node if the parent node is of type nt:folder. Otherwise the node will be created with primary node type nt:resource."
However, while playing around, I found it to be slightly different - The primary node type also depends on the "name" attribute of the <input type="file"> tag. If the input tag has a name attribute which is NOT *, for example, name="image", then the node is created with a name "image" and it has properties jcr:data, jcr:lastModified and jcr:mimeType. However, is the name attribute is *, name="*", then it doesn't matter whether the parent node is of type nt:folder or something else, the node for uploaded file is always created with node type as nt:file only. Regards,Gaurav