All images of plants are coded with a 4 position code, connected with an underscore. The first part is the species code, a three letter abbreviation (see below). The second part is the collector's code. The third part is a greenhouse code. The fourth part is an arbitrarily code, it may be a date, film number or whatever. Unknown or irrelevant data are represented with a letter 'x'. Within a position, data may be separated with a hyphen. This way of coding has some imperfections and is for private use, but you may understand it.
Collectors and growers are normally represented by their full name, followed by the accession code or greenhouse entry number (if known, without blanc's). In the case of 'common names' or very long names I use abbreviations: B - Bastmeijer, Bud - Budianto, CC - Christensen, M - Möhlmann, Mie - Mierendorf, NJ - Niels Jacobsen, NT - Norito Takahashi, SW - Suwidji Wongso etc.
Jacobsen currently uses an extra letter to point the country where the accession is made fe. the letter T for Thailand. Rather common is the use of the year followed by a serial number. A full example: sia_NJT02-14_B881_030810a means a C. cordata var. siamensis, collected by Niels Jacobsen in Thailand in 2002 with serial number 14, cultivated by Bastmeijer with greenhouse entry number 881, the last part is a date of the picture followed with a 'a' to make the full code unique (for database use). As you understand there must be a document regarding the collection: locality (GPS), date, description etc. In general these are not public.
Sasaki uses a locality code instead of a accession code. For example ban_I-BEKB_B934_5939 is a C. bangkaensis collected by Yuji Sasaki in I - Indonesia, BE - the island Beriton (Biliton), KB - sungei Kacang Botok. Grown by B under number 934, the last number is the generated code by the digital camera.
Also Idei uses a locality code but he uses a broad area: A, B, C etc., followed by a serial number. For example ide_B-10A_B1057_7275 is C. ideii, collected by Takashige Idei with code B-10A (B area is near Sampit in Kalimantan). The drawback is that when more collections are made, one must merge it with f .e. the datum to have a unique accession. I often use these codes without the name of the collector for short.