Google Imagen is the image model behind the Gemini app's generation feature, and it is among the strongest at photorealism and following the prompt accurately. For anyone already using Gemini, it is the easiest way to generate high-quality images for free, with higher limits on the paid Google One AI Premium tier.
The limitation is that it lives inside Gemini rather than a dedicated image studio, so you get fewer style controls and editing options than Midjourney or a Stable Diffusion setup. For fast, realistic, free image generation inside a tool you may already use, Imagen is an easy recommendation.