what Dude1 stated won't work. try placing picture1 lower than picture3 and watch, it'll stop. You have to also check if its in the range of picture3 like this

Code:
If Picture1.Left + Picture1.Width >= Picture3.Left And Picture1.Top >= Picture3.Top And Picture1.Top + Picture1.Height <= Picture3.Top + Picture3.Height Then
    'Stop the timer that moves picture1
End If
'You can put this code in the timer that moves picture1, or you can create a timer that checks for collision
'This code only checks for collision between picture1 and picture3, im sure u can now use this code for collision between picture7 and picture3, just change around some numbers.
Also always give your objects names it makes it easier to read

Hope this helps