I set all the image points for each frame to be correct, but when I pin an object to one image point, when the animation runs, the object isn't pinned. Is there an easier way to do this, or do I have to do for each frame active pin the object?
you could try the Pin+ plugin - I think that will do what you want. I see Dop2000 just posted an update that fixes a bug, so look for his download near the end of the thread...
https://www.construct.net/en/forum/extending-construct-2/addons-29/behavior-pin-123766/page-5
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There's also Rex's PinToImagepoint addon:
c2rexplugins.weebly.com/rex_pin2imagepoint.html
Or you can do this with events - simply set position to object's imagepoint on every tick.