Okay, I'll try to give this...can we call it a picture?...a fair review.
Notice that there was no "good" in that sentence before "fair".
Okay, first of all, I'll talk about the background. A horrible background can ruin even the most beautiful art, though this is far from what I'd call "beautiful". Try to put a little more effort into backgrounds. Maybe draw one in pencil and scan it if you have a scanner. At least it wouldn't look like you took the pencil tool and ran it across the screen to separate the sky and ground. (I'm betting that's what you did.)
Now, the recolorings. The schoolboy recolored to look like Max doesn't look all that good. The green covered the outline, and I think you should've used a darker green if you were really trying for Max's shirt color. I can't see the Brock sprite well enough to talk about it because it's rather too small. Jasmine Lover asked why you didn't use the Firered/Leafgreen sprite instead, and I wonder the same thing. At least it would be the same generation as the other sprites. And just what IS that thing over Blaziken's left claw? The legendary birds' attacks aren't drawn very well, either.
Next, the sprites. This is mostly the two "fusions". The Brock/May child sprite looks horribly dreadful. (How does "horribly dreadful" work, anyway?) You took the head from the Brock sprite and put on the May sprite's body. The child can't be two genders at once, you know! A scratch sprite would have been a lot better for that. the same goes for the Blaziken/Swampert fusion/mix. It would probably be a fusion of Torchic's and Mudkip's sprites, for one thing. Not to mention that it would be the female Pokemon's basic form, anyway...
Ah, this is sounding like it requires work, isn't it?
Next comes the speech/thought bubbles. Umi Mizuno said you could've used the circle tool, and I agree with that. I think you could've done better freehanding the thought bubble, but I'm starting to doubt that... Also, Shiny H-oh doesn't even have a speech/thought bubble.
Lastly is the dialogue. What's up with the Shiny Legendary Birds? Is this a sort of alternate universe? Because I'm pretty sure the first movie was BEFORE May and Max came in. And why are the shiny Legendaries there? The really detract from the main idea of the picture, that Brock and May got married.
You're probably wondering why I gave this such a long "review". It's a little-known fact that the worse something is, the more I can ramble on and on about it.