When sending several images in the creation of a marker or object, all of them are visible.

[marcos-mv]

Describe the bug
When sending several images in the creation of a marker or object, all of them are visible on preview.

To reproduce the bug
Steps to reproduce the behavior:

1. Go to 'http://0.0.0.0:8000/users/markers/upload/'
2. Click on 'Choose Object'
3. Choose a object
4. Now choose another object and see all two in the preview.

Expected behavior
Only the last image should be shown as only one is used to generate the marker or object.

Screenshots
Example:

Please, tell us which device/browser is used when finding the bug):

• OS: [ex.: UBUNTU], Browser [ex.: chrome], Version [ex.: 22]

[vjpixel]

The steps to reproduce the bug seems to mix markers and objects.

I've tried both on the Marker and Object upload pages, and it seems ok now.