Each time of opening downloaded file with Gallery app will create a copy accordingly

[TarotChen]

Test Environment:
$ system-image-cli -i
current build number: 228
device name: krillin
channel: ubuntu-touch/rc-proposed/bq-aquaris.en
last update: 2016-01-13 07:38:39
version version: 228
version ubuntu: 20160113
version device: 20160108-efc96d8
version custom: 20151111--36-46-vivid

Steps:
1.Launch browser app
2.Access website: shop.ubuntu.com
3.Tap and hold on an image to download it to Download directory
4.Go to browser settings -> Downloads and tap on the downloaded image
5.Select gallery to open
6.Repeat step4~step5 3 times
7.Back to gallery app and check

Actual result:
There are 3 copies of the same image displayed

Expected result:
End user may not want to create duplicate files and waste the storage space

[Anupam (anupam207)]

related to bug #1443290?