Picture Transfer???

If you're referring to pictures as photos, most don't do well as transfers. Other images will be fine. Epson printers are what you need. Transfers require a specialty ink which is standard in most, but not all Epson models. Check ink type before you buy.

I need to apply a transfer to a shirt...I will print the transfer using pigment ink and then use my heat press to apply the transfer....I am using a jpss transfer

I read that the shirt ha to be 100% cotton or 50/50...

My question is>>> can I use a shirt that is 50% polyester, 25% combed and ringspun cotton, 25% rayon

Shirts don't have to be 100% or 50/50. Other combinations will do well, although I'm not certain how rayon will react. Considering it's only 25%, it may not make a difference.

If it's a white or real light colored shirt you might want to try a sublimation transfer...check with the transfer people to see if that blend is suitable.

if you're doing a photo transfer with jpss on white tees pigment ink will be fine. just set print it at high resolution.

just understand that your customer realizes that inkjet transfers are the lowest quality on the tshirt print method ladder.

Sublimation would be the best for a light colored shirt.