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