You may try this:
Page::where('id', $id)->update(array('image' => 'asdasd'));
There are other ways too but no need to use Page::find($id); in this case. But if you use find() then you may try it like this:
$page = Page::find($id);
// Make sure you've got the Page model
if($page) {
$page->image = 'imagepath';
$page->save();
}
Also you may use:
$page = Page::findOrFail($id);
So, it'll throw an exception if the model with that id was not found.