The website for INAH (Mexico’s Instituto Nacional de Antropologia e Historia) contains a very useful and detailed zoom-able image of Palenque’s Tablet of the Cross, the original of which is now visible in the Museo Nacional in Mexico City. This has been available for a while now, and well worth checking out as an epigraphic/iconographic resource.
It’s important to stress that the right third of the tablet shows extensive restoration, and a number of details of the glyphs are not what they should be. This restoration work took place in several phases, it seems, and goes back to the late nineteenth century, after that section of the tablet was first broken at the ruins, sometime before 1839. The fragments were sent to the U.S. National Museum in Washington D.C. in 1842, and remained there for many decades attracting “considerable attention on the part of numerous visitors” before their eventual return to Mexico. An early photograph of the glyphs published by Charles Rau, in 1879, shows somewhat different restoration work, so clearly the panel had a complex and troubled history.