Starting with WPResidence v.13 we introduced an image size check for images. We did that since many times users upload small images that get stretched or simply don’t look good. The scripts check if the image is at least 500px x 500px.

If you want to change the size we check (or simply disable it) you need to go into

wpresidence/libs/ajax_upload.php 

where you have

if( intval ( $file['base']) ==0){
if( intval($file['height']) false,'image'=>true);
echo json_encode($response);
exit;
}
}

Change the 500 value with the size you  want. If you want to disable the check just delete that code.