Free Image resizer lets resize any image online. Resize photos automatically to fit Instagram, Facebook, Twitter, LinkedIn, YouTube, Google Ads requirments, documents, and other goals. The service provides a huge number of ready presets and an option to resize image with custom parameters. Works great in all browsers (desktop & mobile).
This is a web service supported by all platforms: Windows, Mac OX, iOS, Android. You can use Image Resizer on any device connected to the Internet.