Best AI for Redbubble T-Shirt Designs

Redbubble is one of the largest print-on-demand marketplaces, letting artists upload designs that are printed onto t-shirts, stickers, notebooks, phone cases, and dozens of other products. Unlike Amazon Merch, Redbubble does not require a separate application — anyone can upload and start selling. But to succeed you need designs that look sharp on every product type.

For t-shirts specifically, transparent PNG is critical: Redbubble prints your artwork directly on the garment, and a white background will show as a solid white block on coloured or black shirts. All successful Redbubble merch has a clean cut-out graphic with no background. Resolution should be high enough for large prints — Redbubble recommends high-DPI files for quality apparel output.

The biggest friction point between AI generation and Redbubble upload is background removal. Tools like Midjourney, FLUX, and Stable Diffusion all produce images with baked-in backgrounds — you then need a separate tool to produce a clean transparent cut-out. That adds both cost and time.

MerchBanao includes background removal in the same workflow as generation, layers, and shirt previews. It exports a fixed 4200 × 4800 transparent PNG; adapt that artwork to the current dimensions of each Redbubble product you enable.