KerasHub lets you use pretrained Keras models without recreating their architectures and loading their weights by hand. Its `from_preset()` constructors load named presets; high-level task classes also package common inputs and outputs. For example, `TextToImage` wraps tokenization and diffusion behind `generate()`. section 15.4.2 section 17.3
Listing 17.8 Creating a Stable Diffusion text-to-image model
import keras_hub height, width = 512, 512 task = keras_hub.models.TextToImage.from_preset( "stable_diffusion_3_medium", image_shape=(height, width, 3), dtype="float16", #1 ) prompt = "A NASA astraunaut riding an origami elephant in New York City" task.generate(prompt)
Load a Stable Diffusion 3 preset, set the image shape and dtype, then generate an image from a prompt. section 17.3
Choose the interface for the job. A task such as `ImageSegmenter`, `CausalLM`, or `TextToImage` provides a ready-to-use model. A `Backbone` is useful when you need pretrained features but will build your own prediction head. For text, load a tokenizer that matches the preset: different token IDs would prevent the model from using the representations it learned during pretraining. section 11.3.1 section 15.4.2 section 12.2.2
Listing 15.20 Loading the RoBERTa pretrained model with KerasHub
import keras_hub tokenizer = keras_hub.models.Tokenizer.from_preset("roberta_base_en") backbone = keras_hub.models.Backbone.from_preset("roberta_base_en")
Load the matching RoBERTa tokenizer and backbone from the same preset. section 15.4.2
A practical way to choose a starting point:
- Use `ImageSegmenter.from_preset("sam_huge_sa1b")` for a pretrained segmentation model; this SAM preset has 641 million parameters. section 11.3.1
- Use `CausalLM.from_preset("gemma3_1b")` for text generation, then `compile()` with a sampling strategy and call `generate()`. Downloading these weights requires accepting Gemma’s terms and authenticating with Kaggle. section 16.3.1
- Use a pretrained ResNet `Backbone` and matching `ImageConverter` when attaching a custom YOLO detection head. section 12.2.2
- Use KerasHub’s `SentencePieceTokenizer` layer when preparing token sequences for language-model training; it supports both tokenization and detokenization. section 16.2
Pretrained does not mean effortless or flawless. Training an effective text-to-image diffusion model from scratch is expensive, while generated images can contain visible artifacts. Treat the preset as a practical starting point, and inspect its outputs. section 17.3

