Image buttons Defaulting to PDF not JPEG

So I've created a PDF form that has buttons with the code line : event.target.buttonImportIcon();  and every time I go to add an Image it defaults to PDF. Which means every single time I want to add an Image I have to change PDF to JPEG. This is very time consuming due to the sheer amount of images I have to add.

Is there a way to just have it on JPEG by default?

Also does anyone know of any IOS pdf form filling apps that would allow me to fill a form and also click on those image buttons and instead of adding a file it would just open my camera and I can fill these forms on the go?