I think sombody said it was the "first picture of a PSP game" not sure. I haven't gotten EGM since I got IGN Insider and other game websites.
Still the best EGM April Fool's joke has to be ShenLong in Street Fighter 2. EVERYBODY tried to fight him. You'd see people getting up to M.Bison and just going ape shit when they got hit.
That Shen Long picture was so obviously fake that it wasn't all that good. If you want the best Apirl fool's joke by EGM, it was the first one, when they showed Richter Belmont in TMNT game. It was the first time, so nobody expected it, and it didn't look so out of place like the Shen Long one. I haven't read an EGM in years, so I wonder how good their April fools joke is nowadays.