Targeting functions from other Squid Components

What’s the best practice to target functions in a Squid component from another element? For example, what if I want to create my own button using inline Javascript with an onClick action that will invoke the “Choose File…” action from the File Component ? Visual: Thanks, -David

David, Looking at the elements on a page that has an image, it looks like this is the apex page Iframed in to allow image upload

src="/apex/skuid__UploadImage?id=a0Jd0000009cctHEAQ&objfield=Client_Photo__c&elid=skuid-page-a13d0000000kY38AAE-component-4" 

that page has an apex:inputfile that invokes the skuid uploadimage controller your custom button could probably do the same thing.