clean up sendImage code

src/matrix.coffee

@@ -53,11 +53,12 @@ class Matrix extends Adapter
 
       @robot.logger.info 'found image: downloading...'
 
-      @getImage line, (buffer, info) =>
-        @sendImage envelope, buffer, info, -> done()
+      @downloadImage line, (buffer) =>
+        name = line.split('/')[-1..][0]
+        @sendImage envelope, buffer, name, -> done()
 
 
-  getImage: (imageURL, callback) ->
+  downloadImage: (imageURL, callback) ->
     # process the image a bit
     ne.get imageURL, follow_max: 5, (err, res, body) =>
       gm(body)
@@ -66,15 +67,17 @@ class Matrix extends Adapter
       .resize(360000,'@>')
       .toBuffer (err, buffer) =>
         @robot.logger.info 'image downloaded and processed'
+        callback buffer
 
-        gm(buffer).identify "%m %w %h", (err, format) ->
-          [type, width, height] = format.split ' '
-          callback buffer,
-            mimetype: "image/" + type.toLowerCase()
-            w: width
-            h: height
-            size: buffer.length
-            url: imageURL
+
+  getImageInfo: (buffer, callback) ->
+    gm(buffer).identify "%m %w %h", (err, format) ->
+      [type, width, height] = format.split ' '
+      callback
+        mimetype: "image/" + type.toLowerCase()
+        w: width
+        h: height
+        size: buffer.length
 
 
   sendText: (envelope, text, callback) ->
@@ -85,7 +88,7 @@ class Matrix extends Adapter
     callback() if callback?
 
 
-  sendImage: (envelope, buffer, info, callback) ->
+  sendRawImage: (envelope, buffer, info, callback) ->
     try
       @client.uploadContent(buffer,
         name: info.url
@@ -104,6 +107,14 @@ class Matrix extends Adapter
       callback() if callback?
 
 
+  sendImage: (envelope, buffer, name, callback) ->
+    @getImageInfo buffer, (info) =>
+      @sendRawImage envelope, buffer,
+        url: if name? then name else 'image'
+        mimetype: info.mimetype
+        , callback
+
+
   send: (envelope, lines...) ->
     [..., last] = lines
     if typeof last is 'function'