public/js/upload_queue.js

@@ -17,6 +17,14 @@ UploadQueue.prototype.addEvents = function() {
 				that.hideSpinner();
 				that.submit.disabled = false;
 			};
+
+			if (that.queue.files[0].name.includes(".HEIC")) {
+				alert('Sorry, the HEIC image format is not supported.\nPlease convert your photos to JPEG before uploading.');
+				that.hideSpinner();
+				that.submit.disabled = false;
+				break;
+			}
+
 			that.addPreviewBoxForQueueSlot(i);
 			that.addPreviewForFile(that.queue.files[i], i, callback);
 		};