This is the first paper of a series investigating the scaling relations of early-type galaxies in clusters. Here we illustrate the multi-band imagery and the image reduction and calibration procedures relative to the whole sample of 22 clusters at 0.05<~z<~0.25. We also present detailed surface photometry of 312 early-type galaxies in 7 clusters (A1069, A119, A1983, A2151, A2670, A3125 and DC2103) in the first redshift bin, z=0.025-0.075. We give for each galaxy the complete set of luminosity and geometrical profiles, and a number of global, photometric and morphological parameters. They have been evaluated taking into account the effects of seeing. Internal consistency checks and comparisons with data in the literature confirm the quality of our analysis. These data, together with the spectroscopic ones presented in the second paper of the series, will provide the local calibration of the scaling relations.