Start with new document, fill background with solid green color.
Apply the following layer effect - Gradient overlay, 150%, white-to-black, radial, blend mode = color burn, effect opacity = about 25-30%
Set foreground color to very dark green (almost black but not entirely), select Pen tool, and start drawing very thin curve...
...looking like this.
Resize the curve (Ctrl-T) so that it take a bit more than half of image.
Duplicate this vector many times similar to shown here. There are several ways to do so. One way is to select path with Path Selection Tool (A) and hit Down arrow while holding Shift and Alt keys.
When ready, duplicate this set of shapes and flip them horizontally.
Set the following layer effects for these shapes: blend mode = screen, bladk drop shadow with blend mode = overlay and size = 2-3px.
In new layer, select Pen tool and create a shape with silhouette of a frog. When ready, duplicate the layer (you will need 2 copies of silhouette). Hide one of duplicates.
Create layer mask (Layer menu - Layer mask - Hide all). Then, with large soft white brush, draw inside the mask to only reveal parts of frog silhouette touching the leaf.
Then, hide this layer, select duplicated silhouette, rasterize it...
Apply Gaussian Blur (with large radius, 10-30 px), and set layer opacity to 80%.
Voila! Here is how all our layers look together.
The last touch is: create new layer between frog silhouettes and leaf background, set layer blend mode to overlay, select very large white brush (300px or more) and put very big dot - it will be our light source. That's all!
