QUICK ANSWERStart with the tool that matches your immediate input.
Open Instagram Post Resizer first when its stated purpose matches the result you need now. Use Instagram Story Resizer only when it solves a separate next task.
This guide is for creators, marketers, designers, and website owners. Start with Instagram Post Resizer when your immediate task is to use the Instagram Post Resizer to complete this file task privately in your browser. Move to Instagram Story Resizer only when you also need to use the Instagram Story Resizer to complete this file task privately in your browser.
The goal is not to run two tools automatically. It is to finish the first narrow task, inspect its result, and then decide whether Instagram Story Resizer solves a genuinely different next step.
Both tools sit in Image & Design, but they handle different inputs or outcomes. Keeping those roles separate reduces repeated work and makes verification easier.