Error: spawn EACCES on gulp image resize with ImageMagick

Question

I've found following error on while uploading images.

"showStack":false,"stack":"Error: Error: spawn EACCES\n at finish (/var/www/projects/mywebsite/dist/node_modules/gulp-gm/index.js:40:21)\n at gm. (/var/www/projects/mywebsite/dist/node_modules/gulp-image-resize/node_modules/async/lib/async.js:485:30)\n at emitMany (events.js:127:13)\n at gm.emit (events.js:201:7)\n
at gm. (/var/www/projects/mywebsite/dist/node_modules/gm/lib/getters.js:70:16)\n at cb (/var/www/projects/mywebsite/dist/node_modules/gm/lib/command.js:322:16)\n at gm._spawn (/var/www/projects/mywebsite/dist/node_modules/gm/lib/command.js:226:14)\n at gm._exec (/var/www/projects/mywebsite/dist/node_modules/gm/lib/command.js:190:17)\n at gm.proto.(anonymous function) [as size] (/var/www/projects/mywebsite/dist/node_modules/gm/lib/getters.js:68:12)\n at /var/www/projects/mywebsite/dist/node_modules/gulp-image-resize/index.js:46:16\n at fn (/var/www/projects/mywebsite/dist/node_modules/gulp-image-resize/node_modules/async/lib/async.js:582:34)\n at Immediate. (/var/www/projects/mywebsite/dist/node_modules/gulp-image-resize/node_modules/async/lib/async.js:498:34)\n at runCallback (timers.js:574:20)\n at tryOnImmediate (timers.js:554:5)\n at processImmediate [as _immediateCallback] (timers.js:533:5)","isOperational":true,"level":"error","timestamp":"2016-11-11T15:07:11.378Z"}

I've already changed folder permission to 755 but still encountered error. Please help me how to fix that issue.

I'm using ng-file-upload for file upload.

client code,

this.uploadLogo = function ($files, institute) {
    var def = $q.defer();
    var file = $files[0];
    if (file.size < 5000000) {
        $upload.upload({
            url: 'api/logo',
            method: 'POST',
            file: file,
            data: myformdata
        }).success(function (resp) {
            def.resolve(resp);
        }).error(function (err) {
            def.reject(err);
        });
    }

    return def.promise;
};