Index: media.php
===================================================================
--- media.php	(revision 32266)
+++ media.php	(working copy)
@@ -865,6 +865,10 @@
 			return $src;
 		}
 
+		if ( $return === 'id' ) {
+			return $id;
+		}
+
 		$alt = isset( $desc ) ? esc_attr( $desc ) : '';
 		$html = "<img src='$src' alt='$alt' />";
 		return $html;
Index: class-wp-press-this.php
===================================================================
--- class-wp-press-this.php	(revision 32266)
+++ class-wp-press-this.php	(working copy)
@@ -80,12 +80,19 @@
 				}
 
 				// Sideload image, which gives us a new image src.
-				$new_src = media_sideload_image( $image_src, $post_id, null, 'src' );
+				$image_id = media_sideload_image( $image_src, $post_id, null, 'id' );
+				$src_array = wp_get_attachment_image_src( $image_id, get_option('image_default_size') );
+				$new_src = $src_array[0];
 
 				if ( ! is_wp_error( $new_src ) ) {
 					// Replace the POSTED content <img> with correct uploaded ones.
 					// Need to do it in two steps so we don't replace links to the original image if any.
 					$new_image = str_replace( $image_src, $new_src, $image );
+					// Replace the full image size class name with default image size class name,
+					// if specified.
+					if (get_option('image_default_size') != '' && get_option('image_default_size') !== 'full') {
+						$new_image = str_replace( 'size-full', 'size-' . get_option('image_default_size'), $new_image );
+					}
 					$content = str_replace( $image, $new_image, $content );
 				}
 			}