In short, yes. Shopify resizes images particularly to fit smaller screens. Nevertheless, some images may need manual editing. Please bear in mind that mobile and desktop screens vary. As a result, your UX may vary depending on the screen.
Mobile devices may have a horizontal orientation, whereas desktop screens may have a square or vertical one. As such, rectangular images may not display properly on one screen format or the other. You must, therefore, ensure that your images are square. In doing so, you ensure your images fit properly across various screen sizes.
Also, please remember that Shopify does some light cropping depending on the image’s size. Shopify has a maximum size of 4,000 x 4,000 pixels. Anything bigger than that may become blurry when automatically cropped.
A good rule of thumb is to keep your images within recommended Shopify product image sizes. Then, testing out your product pages helps you visualize what your customers see when they visit your e-commerce site.