The frog is stitched with basic stitches that can be found in the "Heirloom Embroidery Book." The green frog's body is Shadow Embroidered with three strands of floss. (Sorry it doesn't show up well in the photo.) His body is stitched with a Back Stitch, and 3 strands of floss, and his face is stitched with Granito Knots and Back Stitch, using two strands of floss.
After the embroidery was completed, I cut out the front of the shirt and marked the pleats with a blue wash-away marker.