Go for it!! Do you need the original?
Probably, I don't know how to do these.
Well, here is where you make them: http://wigflip.com/automotivator/
Here is Bodhi's Motivational How-To Speech
The source for the pictures is up to you. Make sure you are allowed to use the images you posterize by asking the person who took them if they are OK with that. If not, then you are asking for trouble. Most people are flattered that you want to use their work, so it's not usually a problem. If they are your pictures, you should be OK, but you might want to double check.
Also, we recommend that you only use lower case for the taglines, and as little punctuation as needed. If you have a good idea, find a picture that represents it and then make the tagline work in the least amount of words as possible. Then try and match the color to the color scheme of the image. If the words don't look good on top, try using the bullet lettering method.
And most importantly, have fun and don't feel bad if you get made fun of. It happens to the best of us.
Of course, I'm having trouble finding the original now, I suppose you could crop it out of the one above. I'll keep looking for it.