Fix images in enclosures without MIME type (#3361)

#fix https://github.com/FreshRSS/FreshRSS/issues/3358
Assume enclosures without a mime type, without a length, but with either
a width or a height are images

app/Models/Feed.php

@@ -405,23 +405,23 @@ class FreshRSS_Feed extends Minz_Model {
 						$elinks[$elink] = true;
 						$mime = strtolower($enclosure->get_type());
 						$medium = strtolower($enclosure->get_medium());
+						$height = $enclosure->get_height();
+						$width = $enclosure->get_width();
 						$length = $enclosure->get_length();
-						if ($medium === 'image' || strpos($mime, 'image/') === 0) {
+						if (strpos($mime, 'image') === 0 || ($mime == '' && $length == null && ($width != 0 || $height != 0))) {
 							$enclosureContent .= '<p class="enclosure-content"><img src="' . $elink . '" alt="" /></p>';
-						} elseif ($medium === 'audio' || strpos($mime, 'audio/') === 0) {
+						} elseif (strpos($mime, 'audio') === 0) {
 							$enclosureContent .= '<p class="enclosure-content"><audio preload="none" src="' . $elink
 								. ($length == null ? '' : '" data-length="' . intval($length))
 								. '" data-type="' . htmlspecialchars($mime, ENT_COMPAT, 'UTF-8')
 								. '" controls="controls"></audio> <a download="" href="' . $elink . '">💾</a></p>';
-						} elseif ($medium === 'video' || strpos($mime, 'video/') === 0) {
+						} elseif (strpos($mime, 'video') === 0) {
 							$enclosureContent .= '<p class="enclosure-content"><video preload="none" src="' . $elink
 								. ($length == null ? '' : '" data-length="' . intval($length))
 								. '" data-type="' . htmlspecialchars($mime, ENT_COMPAT, 'UTF-8')
 								. '" controls="controls"></video> <a download="" href="' . $elink . '">💾</a></p>';
-						} elseif ($medium != '' || strpos($mime, 'application/') === 0 || strpos($mime, 'text/') === 0) {
+						} else {	//e.g. application, text, unknown
 							$enclosureContent .= '<p class="enclosure-content"><a download="" href="' . $elink . '">💾</a></p>';
-						} else {
-							unset($elinks[$elink]);
 						}
 
 						$thumbnailContent = '';