Get better stitch files by preparing artwork the right way.
Solid colours digitize far better than gradients or photographs. Aim for 300+px on the shortest side.
Merge similar shades and set a sensible thread limit — every colour is a thread change on the machine.
Lettering below ~4mm cap height distorts. Enlarge it or send to manual review.
Photographic content and soft shadows aren't sewable automatically; StitchFlux will flag them.
Stretchy knits need more pull compensation and underlay than woven canvas.