Open reference picture in photoshop
Open snail file, from which selection can be drag to butterfly reference file. You can also copy selection from source file using Edit > Copy menu command and then paste it into butterfly reference file using menu Edit > Paste command.
Select portion of source as shown in picture with the help of lasso tool or pen tool. Then Press V button to select "Move Tool" and drag this selection to reference file.
Press ctrl+t for "Free Transform tool", then resize and place it correctly to cover upper right wing of butterfly.
From filter menu choose command liquify
Tick mark on Show backdrop , use background from combo list and set opacity to 67. Set Brush size to 151, (it can be set to lower values in next step, when using for small and narrow areas.)
Use "Forward warp tool" tool and pull snail shell slightly inward the wing (which are outside the wing) to reshape it correctly. For this step set brush size to 207.
Further refine using same "forward warp tool"
When finished, click ok. Using liquify tool need some practice and patient. Here is our reshaped wing of butterfly.
Now press ctrl+J to duplicate this layer. Choose Flip Horizontal command from Edit > Transform menu.
Move and position new layer as shown in picture.
Now drag same selection from snail image for lower wing. Press ctrl+t for Free Transform and resize it to cover the whole bottom wing.
Use Filter > Liquify command and reshape wing using "Forward warp Tool". There is zig-zag pattern in lower wing edge, therefore reduce brush size to around 50-60 and pull these parts inward.
Use "forward warp tool" with small brush size and small stroke.
The lower wing completed so far. Click Ok.
Now press ctrl+J to duplicate this layer and flip it horizontally, as we done in previous steps.
Select snail body from source image and drag it to butterfly reference file.
Make sure it should be top most layer.
Now rotate and resize it using "Free Transform tool" (ctrl+t)
Reshape snail body and antena using Filter > Liquify tool with the help of "forward warp tool"
Creation of butterfly is completed. Now we need some background.
Select and drag leave portion from source to butterfly file and use free transform to resize it..
Make sure that leave background should be bottom most layer.
Finally blur background with Filter > Blur > Gaussian Blur with the setting of 8.
Final result of tutorial.