Step 1. Login to your instagram account on chrome browser.
Step 2. After login, you won’t find any option for posting an image on your screen.
Step 3. Press F12 on the keyboard, it would open chrom developer tools.
Step 4. In the top, click on the responsive dropdown and select a mobile device like Nexus 5 from that dropdown.
Step 5. Reload the page and now you see it opens as a mobile screen, now you can click the ‘+‘ button and post something on instagram right from your PC.