Start by opening an image of room with fireplace.
Create selection of the flames using polygon lasso tool. Press Ctrl+J to copy paste the selection in a new layer.
From "Filter" menu select "Liquify". Select forward warp tool and stretch the edges a bit.
Duplicate the layer and repeat this step again. Now we've three different position of flames.
Select the background layer. Create a rectangle using rectangular shape tool. Press Alt+Ctrl+D to feather the selection. Feather the selection by 10 pixels.
Press Ctrl+J to copy paste the selection in a new layer. Press Ctrl+L to open level settings. Apply settings as shown.
Similarly cerate another layer. Adjust the levels according to the flame size. If there are big flames, try to make the ambience more illuminated by adjusting levels accordingly.
Open animation window. For the first frame hide all the layers except the original layer.
Duplicate frame. Unhide the second flame and brick selection layer.
Duplicate frame. Hide the previous ones and unhide the next ones.
Press Ctrl+Alt+Shift+S to save an optimized animated GIF.
