1. A photographic element comprising a support having thereon a photosensitive layer which contains: a. at least one heterocyclic photochromic spiropyrane which can exist in two forms and is selectively converted from one form to the other on irradiation according to the scheme ##STR6## wherein R.sub.3 is methyl, phenylthio, phenyl, chloro, bromo, methoxy, hydroxy, naphthyl, 4-chlorophenyl, 4-bromophenyl, 4-hydroxyphenyl, or 4-methoxyphenyl; R.sub.3 ' is methyl, isopropyl, n-hexyl, benzyl, or phenylethyl; R.sub.6 is nitro; R.sub.6 ' is hydrogen, methylthio or phenylthio; R.sub.8 is methoxy; and X is thio, seleno, imido, oxo, aza, or dialkylcarbo; .lambda..sub.1 is a wavelength in the ultraviolet range and .lambda..sub.2 is a wavelength in the visible range; b. at least one ortho-substituted nitrogen-containing heterocyclic thioether of the following formula: ##STR7## wherein ##STR8## Z is a group of atoms required to complete a five-membered ring or a five-membered substituted ring, R.sub.1, R.sub.2, and R.sub.2 ' are alkyl or acylalkyl groups, the open form of the spiropyrane being capable of acting as a catalyst in the conversion of the thioether to a thione in accordance with the following reaction: ##STR9## so that a latent image produced on exposure of the spiropyrane to light is amplified, c. at least one agent for producing a visible image from the amplified latent image, such agent comprising 1. at least one metal salt of a carboxylic acid which can be reduced by thiones and is a behenate, resinate, naphthenate, benzoate, or stearate of silver, cadmium, calcium, copper, cobalt, tin, manganese, magnesium, nickel, lead, or zinc, or 2. at least one compound which together with the thione, forms a complex of the formula: EQU ML.sub.2 where M represents halide or thiocyanate and L represents the thione, and is zinc, cobalt, or nickel halide or zinc or cobalt thiocyanate, and d. at least one component which will fix the spiropyrane in the open form, such component being a semiconducting oxide or a cobalt, copper, or nickel salt.