imageRouter/filesystem: make callback path-independent

Images are now properly served when `config.uploadsPath`
differs from its default value.

Signed-off-by: WilliButz <wbutz@cyberfnord.de>

lib/web/imageRouter/filesystem.js

@@ -1,5 +1,6 @@
 'use strict'
 const url = require('url')
+const path = require('path')
 
 const config = require('../../config')
 const logger = require('../../logger')
@@ -15,5 +16,5 @@ exports.uploadImage = function (imagePath, callback) {
     return
   }
 
-  callback(null, url.resolve(config.serverURL + '/', imagePath.match(/public\/(.+)$/)[1]))
+  callback(null, url.resolve(config.serverURL + '/uploads/', path.basename(imagePath)))
 }