Re the famous painting you mention, Dayan Yakov Kalvary is noted as accompanying Rabbi Akiva four times in the Julius Knorr painting, Der Marktplatz in Posen, which if I am reading this correctly can be found in the Israel Museum Archives.
ie. http://www.wbc.poznan.pl/Content/381538/Jews%20of%20Posen%20Provinc...
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Cohen, Richard I. [Yerachmiel], “‘And Your Eyes Shall See Your Teachers’: The Rabbi as Icon,” Ts, Vol. 58, 1993, No. 4, pp. 407-452. Re: Akiba Eger, pp. 422-431. Discussion of the Julius Knorr painting, Der Marktplatz in Posen, p. 424; “Our Rabbi Akiva Eger, z”l [Zichrono livracha—of blessed memory] when he was 74 years of age in a street in the city of Posen, accompanied by two rabbinic judges of the city, R. Jacob Kalvary and R. Moshe Landsberg z”l,” p. 425; and two other portraits of Eger, p. 427. See also next entry. For additional information, see “d. The Israel Museum” in the chapter on Israeli Archival Sources.
—, Jewish Icons: Art and Society in Modern Europe, Berkeley: University of California Press, ©1998, 358 pp., including notes, pp. 261- 318, bibliographical references, pp. 319-348, and index, pp. 349-358. N7415.C556 1998. “The Popularization of the Rabbinic Figure: The Case of Akiba Eger,” pp. 128-134, and notes 35-53, pp. 287-289. Reproduction of the Julius Knorr painting, Der Marktplatz in Posen, p. 129 and note 40, p. 288; “Our Rabbi Akiva Eger, z”l [Zichrono livracha—of blessed memory], when he was 74 years of age in a street in the city of Posen, accompanied by two rabbinic judges of the city, R. Jacob Kalvary and R. Moshe Landsberg z”l,” p. 130 and not 41, p. 288, as described on p. 129 [erroneously indicating that the buildings in the background are from the Knorr painting]; three other portraits of Eger reproduced on pp. 131, 132, and 133. See also the previous entry. (Scroll p.1308) http://www.wbc.poznan.pl/Content/381538/Jews%20of%20Posen%20Provinc...
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“Stary Rynek od Zachodu” (Old Market Viewed from the West), Juliusz Knorr, ok. 1838, oil on canvas, 2,64x2,31 m, Pozna1⁄2 Historical Museum: In the middle of the crowd there is a group of Jewish street peddlers; in the opposite corner is Rabbi Akiba Eger walking with the assistance of persons identifiable as Moses Landsberger and Jacob Kalvary.
(Scroll p. 77) http://www.wbc.poznan.pl/Content/381538/Jews%20of%20Posen%20Provinc...
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In Prints and Drawings Division, there are three items of interest:
1. “The Great Learned Rabbis of Israel,” Graph-Kunstantalten Breslau, “Made in Germany.” No. 1556-5-43 in Box 71: Portraits. Akiba Eger of Posen pictured on top right; his son, Salomon Eger of Posen, on bottom, fourth from right. The same item is illustrated in Cohen, Richard I. [Yerachmiel], “‘And Your Eyes Shall See Your Teachers’: The Rabbi as Icon,” Tsiyon, Vol. 58, 1993, No. 4, pp. 407-452, at p. 446. See also Cohen, Richard I., Jewish Icons: Art and Society in Modern Europe, Berkeley: University of California Press, ©1998, 358 pp., including bibliographical references, pp. 319-348, and index, pp. 349-358. N7415.C556 1998. “The Popularization of the Rabbinic Figure: The Case of Akiba Eger,” pp. 130-134, and notes, pp. 287-288. Reproduction of the Julius Knorr painting, Der Marktplatz in Posen, p. 129; “Our Rabbi Akiva Eger, z”l [Zichrono livracha—of blessed memory], when he was 74 years of age in a street in the city of Posen, accompanied by two rabbinic judges of the city, R. Jacob Kalvary and R. Moshe Landsberg z”l,” (Scroll to P. 85) http://www.wbc.poznan.pl/Content/381538/Jews%20of%20Posen%20Provinc...