Gramblr

Gramblr is a simple tool that allows you to upload photos to Instagram directly from your computer, and for that you don't need a mobile phone at all.

All you have to do is log in with your username and password and then select the photo you want to upload. You won't be able to upload any photo - it should be a square image, with a minimum size of 640 x 640 pixels, so as not to violate Instagram's standard requirements.

In its interface, Gramblr recommends using a site that makes a photo square, although you can always use any photo editor. Once the JPG photo is ready, all you have to do is press the download button.

Then you will need to add a caption to the photo, and after the photo is uploaded, you will be able to use all the same options that are available in the mobile app: you can share your photo on Facebook or Twitter.

Although the app does not have the ability to add effects and you will have to put up with the lack of filters, it is still a very good option to download photos from your computer, because the web version of Instagram does not offer such a feature.