See the new collection of transfers here: Portfolio Photo Transfers

Selection of Photo Transfer Tiles, 5 W x 6 L inches – 12.7 W x 15.2 L Centimeters each

There are many techniques to use the photo transfer process with clay with a variety of supplies, including underglaze transfer paper, decal transfer paper, screen printing, or even photo copy paper. Depending on the paper and the process, transfers can be done on wet clay, bisqued but not glazed clay, and on glazed clay (technique I use.)

Ceramic Arts Network has nice series on these different methods:

https://ceramicartsnetwork.org/daily/ceramic-supplies/ceramic-glazes-and-underglazes/carbon-copy-underglaze-transfer-paper-makes-easy-transfer-images/

https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-decorating-techniques/easy-approach-image-transfer-onto-clay/

https://ceramicartsnetwork.org/daily/ceramic-supplies/ceramic-colorants/photo-lithography-on-clay-a-surprisingly-simple-way-to-print-images-on-clay/

https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-decorating-techniques/how-to-make-your-own-hand-drawn-screens-for-screen-printing-on-clay/

This technique/paper lets you do the transfer process on a bisqued piece with a Cone 6 glazing:

https://bigceramicstore.com/pages/info-ceramics-tips-tip104_one_fire_technique

Paper Source and Instruction Book

https://bigceramicstore.com/products/fired-on-images-for-ceramics-porcelain-and-glass-banhazl

https://bigceramicstore.com/products/fired-on-decal-paper-10-pk