I just successful add my instagram photo to my blog..
and it's really easy.. I'm using SnapWidget

Click the link and start customize your widget..
Here is the example..,

I choose a Grid Type...
most sidebar width are between 200-300px, if you want to make 2x2 layout you need to set 100px or 150px for the thumbnail size

Actually there are 5 widget type: grid, board,  scrolling, slideshow and map..
If you want to see the difference you can click Preview button...

When you are ready to put the widget, you can get a code by clicking Get Widget button...


Now you just only need to copy and paste the code to HTML Widget on your blog's layout

Click Save and here's the result