Question: Is there an online tool that can enlarge images up to 16000x16000 pixels?

The Smart Image Upscaler is a capable online tool that can increase image size up to 400%, with a maximum size of 16000x16000 pixels. It also can process groups of images in batches, use different upscaling models for different types of images, and offer some controls to fine-tune results. It can handle JPG, PNG and JPEG files, and offers free and paid options.

Another good option is Bigjpg, a lossless image enlarger that uses deep convolutional neural networks to try to preserve color, detail and edges. It can increase images up to 16x their original size, good for anime-style artwork and regular photos, too. The service offers a few different pricing levels, and it protects privacy by deleting uploaded images after three days.

If you need more advanced abilities, Let's Enhance offers AI-powered image enhancement and generation. It can increase and otherwise improve low-resolution images up to 4K and beyond, and offers tools for batch processing, HDR filters and background removal. It's geared for creative professionals, eCommerce and real estate.