Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
jpg does not support transparency. you would likely need to flatten your transparent image with some background color first. Or save your output as png or gif or tif
try this, it works for me. note your large image has two frames and a virtual canvas. use +repage to remove the virtual canvas and use just the first frame.
convert zahnarzt1.gif[0] stamp.png +repage -gravity south -geometry +0+10 -compose over -composite result.gif
Fred however is right you have two frames with slight differences in 'dithering', Especially in E-Dither 'speckle' on the Ken Doll's pants. But no real animated differences between the two frames.
For more help more detail of what you want to achieve is needed.