checkImgExists(imgurl) {
			        var ImgObj = new Image(); //判断图片是否存在  
			        ImgObj.src = imgurl;
			        console.log(ImgObj.fileSize);//打印出来是undefined
			        //没有图片,则返回-1  
			        if (ImgObj.fileSize > 0 || (ImgObj.width > 0 && ImgObj.height > 0)) {
			            return true;
			        } else {
			            return false;
			        }
			},
uni
 uni.getImageInfo({
			                 src: imgurl,
			                 success: function (image) {
								  console.log(image);
			                     console.log(‘存在‘);
			                 },
							 fail: function (image) {
								  console.log(image);
			                     console.log(‘不存在‘);
			                 },
			             });
原文:https://www.cnblogs.com/jyc226/p/14869693.html