EMAN2 includes a good selection of test images that can be generated in no time at all. They come in many shapes and forms, from simple gradients and shapes to basic noise models. To create a test image start by running e2.py and by creating an empty image that is appropriately sized, for example as follows: 

#] e2.py

Welcome to EMAN2
Prompt provided by IPython
Enter '?' for ipython help

In [3]: e = EMData()

In [4]: e.set_size(256,256)

Then issue one of the commands embedded below in the table to generate the test image

attachment:xcoord.png

attachment:ycoord.png

 e.process_inplace("testimage.gradient")

 e.process_inplace("testimage.gradient", {'axis','y'}) 

attachment:axes.png

attachment:circle.png

 e.process_inplace("testimage.axes")

 e.process_inplace("testimage.circlesphere") 

attachment:scurve.png

attachment:gaussnoise_large.png

 e.process_inplace("testimage.scurve")

 e.process_inplace("testimage.noise.gauss") 

Finally, you can display the image 

In [5]: e.process_inplace("testimage.scurve")

In [6]: display(e)