Using AI Models

As an addition to the built-in TensorFlow models, PhotoPrism lets you generate captions and labels with Ollama and the OpenAI API. Our step-by-step guides explain how to set them up and provide tested configuration examples you can use as a starting point.

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Model Engines

PhotoPrism currently supports the following runtimes and services:

Engine	Resolution	Runs	Best For
TensorFlow	224 px	Built-in	Fast, offline default models for core features (labels, faces, NSFW)
Ollama	720 px	Self-Hosted	Good for generating quality captions & labels; a server with GPU is recommended
OpenAI API	720 px	Cloud	Highest quality captions & labels, also suitable for users without a GPU; requires API key and network access

Performance

• TensorFlow: Our built-in models generally perform well on all types of hardware.
• Ollama: Generating labels for an image on an NVIDIA RTX 4060 usually takes 1-4 seconds. The exact time varies depending on the model used and the number of labels generated.
• OpenAI: Processing one image takes about 3 seconds, though this can vary by model, region, and demand.

Without GPU acceleration, Ollama models will be significantly slower, taking anywhere from 10 seconds to over a minute to complete. This may be acceptable if you only want to process a few pictures or are willing to wait.

vision.yml Reference

Custom AI engines, models, and run modes can be specified in a vision.yml file located in the storage/config directory. The file defines a list of models and thresholds to be used, e.g.:

Models:
- Type: caption
  Model: gemma3:latest
  Engine: ollama
  Run: auto
  Options:
    Temperature: 0.05
  Service:
    Uri: http://ollama:11434/api/generate
- Type: labels
  Model: qwen3-vl:latest
  Engine: ollama
  Service:
    Uri: http://ollama:11434/api/generate
Thresholds:
  Confidence: 10
  Topicality: 0
  NSFW: 75

If a model type is omitted, PhotoPrism will use the built-in defaults for labels, nsfw, face, or caption. The optional Thresholds block can be used to filter out labels with a low probability or adjust the probability of flagging content as NSFW.

Field	Default	Notes
Type (required)	—	labels, caption, face, nsfw. Drives routing & scheduling.
Model	""	Raw identifier override; precedence: Service.Model → Model → Name.
Name	derived from type/version	Display name; lower-cased by helpers.
Version	latest (non-OpenAI)	OpenAI payloads omit version.
Engine	inferred from service/alias	Aliases set formats, file scheme, resolution. Explicit Service values still win.
Run	auto	See Run modes table below.
Default	false	Keep one per type for TensorFlow fallbacks.
Disabled	false	Registered but inactive.
Resolution	224 (TensorFlow) / 720 (Ollama/OpenAI)	Thumbnail edge in px; TensorFlow models default to 224 unless you override.
System / Prompt	engine defaults / empty	Override prompts per model.
Format	""	Response hint (json, text, markdown).
Schema / SchemaFile	engine defaults / empty	Inline vs file JSON schema (labels).
TensorFlow	engine defaults / empty	Local TF model info (paths, tags).
Options	engine defaults / empty	Sampling/settings merged with engine defaults.
Service	engine defaults / empty	Remote endpoint config (see below).

Run Modes

Value	When it runs	Recommended use
auto	TensorFlow defaults during index; external via metadata/schedule	Leave as-is for most setups.
manual	Only when explicitly invoked (CLI/API)	Experiments and diagnostics.
on-index	During indexing + manual	Fast built-in models only.
newly-indexed	Metadata worker after indexing + manual	External/Ollama/OpenAI without slowing import.
on-demand	Manual, metadata worker, and scheduled jobs	Broad coverage without index path.
on-schedule	Scheduled jobs + manual	Nightly/cron-style runs.
always	Indexing, metadata, scheduled, manual	High-priority models; watch resource use.
never	Never executes	Keep definition without running it.

For performance reasons, on-index is only supported for the built-in TensorFlow models.

Options

Adjusts model parameters, such as temperature and top-p, as well as other constraints, when using Ollama or OpenAI:

Option	Engines	Default	Description
Temperature	Ollama, OpenAI	engine default	Controls randomness with a value between 0.01 and 2.0; not used for OpenAI's GPT-5.
TopK	Ollama	engine default	Limits sampling to the top K tokens to reduce rare or noisy outputs.
TopP	Ollama, OpenAI	engine default	Nucleus sampling; keeps the smallest token set whose cumulative probability ≥ p.
MinP	Ollama	engine default	Drops tokens whose probability mass is below p, trimming the long tail.
TypicalP	Ollama	engine default	Keeps tokens with typicality under the threshold; combine with TopP/MinP for flow.
TfsZ	Ollama	engine default	Tail free sampling parameter; lower values reduce repetition.
Seed	Ollama	random per run	Fix for reproducible outputs; unset for more variety between runs.
NumKeep	Ollama	engine default	How many tokens to keep from the prompt before sampling starts.
RepeatLastN	Ollama	engine default	Number of recent tokens considered for repetition penalties.
RepeatPenalty	Ollama	engine default	Multiplier >1 discourages repeating the same tokens or phrases.
PresencePenalty	OpenAI	engine default	Increases the likelihood of introducing new tokens by penalizing existing ones.
FrequencyPenalty	OpenAI	engine default	Penalizes tokens in proportion to their frequency so far.
PenalizeNewline	Ollama	engine default	Whether to apply repetition penalties to newline tokens.
Stop	Ollama, OpenAI	engine default	Array of stop sequences (e.g., ["\\n\\n"]).
Mirostat	Ollama	engine default	Enables Mirostat sampling (0 off, 1/2 modes).
MirostatTau	Ollama	engine default	Controls surprise target for Mirostat sampling.
MirostatEta	Ollama	engine default	Learning rate for Mirostat adaptation.
NumPredict	Ollama	engine default	Ollama-specific max output tokens; synonymous intent with MaxOutputTokens.
MaxOutputTokens	Ollama, OpenAI	engine default	Upper bound on generated tokens; adapters raise low values to defaults.
ForceJson	Ollama, OpenAI	engine default	Forces structured output when enabled.
SchemaVersion	Ollama, OpenAI	derived from schema	Override when coordinating schema migrations.
CombineOutputs	OpenAI	engine default	Controls whether multi-output models combine results automatically.
Detail	OpenAI	engine default	Controls OpenAI vision detail level (low, high, auto).
NumCtx	Ollama, OpenAI	engine default	Context window length (tokens).
NumThread	Ollama	runtime auto	Caps CPU threads for local engines.
NumBatch	Ollama	engine default	Batch size for prompt processing.
NumGpu	Ollama	engine default	Number of GPUs to distribute work across.
MainGpu	Ollama	engine default	Primary GPU index when multiple GPUs are present.
LowVram	Ollama	engine default	Enable VRAM-saving mode; may reduce performance.
VocabOnly	Ollama	engine default	Load vocabulary only for quick metadata inspection.
UseMmap	Ollama	engine default	Memory map model weights instead of fully loading them.
UseMlock	Ollama	engine default	Lock model weights in RAM to reduce paging.
Numa	Ollama	engine default	Enable NUMA-aware allocations when available.

Service

Configures the endpoint URL, method, format, and authentication for Ollama, OpenAI, and other engines that perform remote HTTP requests:

Field	Default	Notes
Uri	engine default	Service endpoint URL. Empty for local models.
Method	POST	Override only if provider needs it.
Key	""	Bearer token; supports env expansion (OpenAI: OPENAI_API_KEY, Ollama: OLLAMA_API_KEY1).
Username / Password	""	Injected as basic auth when Uri lacks userinfo.
Model	""	Endpoint-specific override; wins over model/name.
Org / Project	""	Organization / Project ID when using OpenAI.
RequestFormat / ResponseFormat	engine default	Explicit values win over engine defaults.
FileScheme	engine default	Controls image transport e.g. data or base64.
Disabled	false	Disables the endpoint without removing the model.

Authentication: All credentials and identifiers support ${ENV_VAR} expansion. Service.Key sets Authorization: Bearer <token>; Username/Password injects HTTP basic authentication into the service URI when it is not already present. When Service.Key is empty, PhotoPrism defaults to OPENAI_API_KEY (OpenAI engine) or OLLAMA_API_KEY¹ (Ollama engine), also honoring their _FILE counterparts.

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1. Can be used with our preview build and in the next stable release. ↩↩