Problem is destinationType: this.camera.DestinationType.FILE_URI,

you are sending, file url over http and not the base64 of image

Change your destination type:
destinationType: this.camera.DestinationType.DATA_URL,

DATA_URL Return base64 encoded string. DATA_URL can be very memory intensive and cause app crashes or out of memory errors. Use FILE_URI or NATIVE_URI if possible

UPDATE

In this video you can check how to send base64 to api as File

https://www.youtube.com/watch?v=tph5Nk4Ab1g

I’m currently developing a Android app where the user can take his or hers picture and upload it to a PATCH API endpoint that would listen to the key ‘avatar’.

I’m using the Cordova Camera and the Advanced HTTP plugin to handle it.

Below is the function that triggers when taking a photo.

takePicture() {
    const options: CameraOptions = {
      quality: 50,
      destinationType: this.camera.DestinationType.FILE_URI,
      encodingType: this.camera.EncodingType.JPEG,
      mediaType: this.camera.MediaType.PICTURE,
      correctOrientation: true,  // Corrects Android orientation quirks
      allowEdit: false, // Post process aanpassingen
      sourceType: this.camera.PictureSourceType.CAMERA // Pak de selfie camera
    };
    this.camera.getPicture(options).then((imageData) => {
      const formData = new FormData();
      formData.append('avatar', imageData, 'pic.jpg');
      this.web.updateUserInfo(formData).subscribe(() => {});
    }, (err) => {
      console.error('Camera Error: ' + err);
    });
  }

Here is the API handling

updateUserInfo(newData: any) {
        return new Observable((obs) => {
                this.http2.patch('localhost/user', {newData}, {
                    'X-Subdomain': 'host',
                    'X-Token': this.apiKey,
                }).then(() => {console.log('Camera API success!'); obs.next(); }).catch(error => {
                    console.error(error);
                });
        });
    }

No errors are being given out so it is hard for me to see where the issue is. I have little experience working with Cordova and Ionic so this is all new to me.