I would like to add to and clarify some of the replies you have received, as well as offer some more information. I have many ancestors and relatives buried in the Lodz Jewish cemetery and I have been there twice, in 2016 and in 2019, and have explored the cemetery at length.
Firstly, you have already done the most logical thing by writing to the Jewish community which looks after the cemetery. They do searches for gravesites on request and will probably send you a photo of the site. Please be aware that they are likely to charge a fee for this.
Find-a-Grave, mentioned earlier, as far as I know has next to nothing from Poland. Also, the .jpg reference mentioned earlier is not a picture of the gravesite but of the gravesite's listing in the burial records. The cemetery's website has general pictures in which individual tombstones can be seen, but unfortunately it does not have photos linked to names. In addition, the Museum of the City of Lodz mentioned earlier, while interesting in itself, does not have information about the burials in the Jewish cemetery. So those sources will not be of use to you. Finally, the Germans did not keep records of the burials in the ghetto field or the cemetery in general during the war or at any other time, the Jewish community kept and still keeps the burial records from there.
You may be interested to know that there are approximately 60,000 surviving individual burial cards (out of about 180,000 burials) that the Jewish community has in its offices, which are currently being digitized in a project with the Polish archives. These burial cards can be little treasure troves of information, as they state not only the deceased's name, age, sometimes the father's name, date of death, date of burial, and gravesite, but they also often state the address from which the deceased was brought to burial, so you can learn where your relative was when he or she died. If interested, you could inquire from the community if they have the burial card for your relative.
Back to the cemetery. As Bernard correctly wrote, those who died inside the ghetto, some 43,500-45,000 people, were usually buried in the so-called ghetto field. They were buried in individual, measured plots, but they had no matzevot or signs on them. Since the war, some of the graves in the ghetto field have been marked with plaques in a project done (I believe with the Israeli army) some years ago, but most have not. Also, some of the graves have received actual matzevot since the war, usually placed by surviving relatives. That was the case with my own great-grandfather, Szmul Aron Bulwar z"l, who died in the ghetto in January 1941. Below I am inserting a photo in which you can see my great-grandfather's grave, with here and there in the field other matzevot placed since the war poking up through the grass. But as you can see most graves do not have any kind of marking on them.
A number of people who died inside the ghetto were not buried in the ghetto field but in the older part of the cemetery, which had matzevot. Such people would not have had any matzevah of their own, but would have been buried under or next to the matzevah of the relative who was earlier buried there. This is worth keeping in mind too when searching for relatives' burial sites.
As is well known, the Jewish community was decimated in the Holocaust and after the war most of the survivors left Poland, so the cemetery fell into disrepair and neglect. In the older (pre-war) part of the cemetery, many matzevot have deteriorated and become illegible and/or broken, and vegetation and even large trees have grown up through the graves, completely destroying matzevot. Some have also fallen prey to human vandalism. Despite this, many matzevot, especially in the central area around the main paths, do still stand and are legible and in surprisingly good condition. It must be said that efforts have been made in recent years to clean up and maintain the cemetery, including by Polish volunteers who deserve commending for their work there.
I hope the above information assists you, and I wish you luck in your efforts to obtain a photo. Below I am inserting various photos from the cemetery, taken on my visit there in 2019, so that you can see the conditions. I have including the one mentioned above of my great-grandfather's grave in the ghetto field, and another one in the older part of the cemetery of the matzevah of his father, my great-great-grandfather, Chaim Leib Bulwar z"l, who died in 1921.
All the best,
Miriam Bulwar David-Hay,
Professional journalist, writer, editor, proofreader.
Professional translator (Hebrew/Yiddish to English).
Certified guide, Yad Vashem Holocaust Memorial and Museum.
Researching: BULWA/BULWAR (Rawa Mazowiecka, Lodz, Paris); FRENKIEL/FRENKEL, FERLIPTER/VERLIEBTER (Belz); KALUSZYNER, KUSMIERSKI, KASZKIET, KUZKA, JABLONKA, RZETELNY, WROBEL (Kaluszyn, Lodz); KRYSKA/KRYSZKA, CHABIELSKI/HABELSKI (Sieradz, Lodz); LICHTENSZTAJN (Kiernozia, Wyszogrod, Lodz); ROZENBERG (Przedborz, Lodz); WAKS (Nowe Miasto nad Pilica, Lodz); PELCMAN, STORCZ (Rawa Mazowiecka); SOBEL (Paris); SAPIR/SZAFIR (Wyszogrod).