3647×2086，2.44M的jpg文件，我在Canvas 2d中用1920×1098绘制，wx.canvasToTempFilePath保存后，文件大小变成了4.087M，更换手机型号，大小有小量的变化。代码如下： var canvas = param._this.data.imgCavObj;             canvas.width = param.size.canvas_w * param._this.data.dpr;             canvas.height = param.size.canvas_h * param._this.data.dpr;             var ctx = param._this.data.imgCtx;             ctx.scale(param._this.data.dpr, param._this.data.dpr);             ctx.clearRect(0, 0, param.size.canvas_w, param.size.canvas_h);             var img = param._this.data.cavImg;             img.src = param.imgpath;             img.onload = () => {               ctx.drawImage(img, 0, 0, param.size.canvas_w, param.size.canvas_h);               wx.canvasToTempFilePath({                 destWidth: param.size.canvas_w,                 destHeight: param.size.canvas_h,                 canvas: canvas,                 fileType: "jpg",                 quality: 0.3,                 success: function (res) {                   if (param.success) param.success(res);                 },                 fail: function (res) {                   if (param.fail) param.fail(res);                 }               }, param._this);             } 我想要的是文件大小变小，结果变大了。改变quality，文件大小也没有变化。