WebPrepImage

WebPrepImage is a lightweight Windows utility designed to prepare images for web use in a predictable way. It resizes images by maximum long edge and then reduces JPEG quality only if required to meet a specified file size limit. This eliminates guesswork when preparing images for platforms with strict size constraints. The application runs entirely locally and does not upload files.

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• Resize by longest edge. This core function resizes the image by adjusting its longest side (width or height) to a user-defined maximum value while maintaining the original aspect ratio. It ensures all images in a batch have uniform dimensions without distortion, which is critical for web galleries and design templates that enforce maximum display sizes.
• JPEG file size limiting. This feature allows setting a maximum file size in kilobytes (KB) for the output image. The algorithm processes the image starting at maximum quality (100) and progressively reduces it until the resulting file does not exceed the specified limit, or until it reaches a defined minimum quality. It guarantees images meet server or CMS upload limits without manual trial and error.
• Manual JPEG quality adjustment. The user can choose to set a specific JPEG compression level (1 to 100), ignoring the file size limit. This mode is useful when a predictable balance between visual quality and file weight is required, for instance, to preserve a certain texture in product photography.
• Batch processing. The tool enables selecting multiple image files and processing them sequentially with identical resizing and compression parameters. It automates the preparation of large image sets for web catalogs, saving time and ensuring consistency across the entire batch.
• EXIF metadata writing (Copyright/Artist). WebPrepImage can insert or overwrite the EXIF Copyright and Artist fields in processed images. This allows embedding authorship information directly into the files, a recommended practice for copyright protection in web content.
• Preservation of original EXIF metadata. In addition to writing new fields, the application retains other EXIF metadata (such as camera, date, GPS) during resizing, unless instructed otherwise. This maintains technical information associated with the image, useful for photographers and stock image agencies.
• Output file size preview. Before processing, the interface displays an estimate of the final file size based on the selected parameters (dimensions and quality). This information helps fine-tune the configuration without performing iterative tests.
• Grayscale conversion mode. A dedicated option converts images to grayscale (black and white) during processing. Specific for preparing images for black-and-white printing or for reducing file weight in contexts where color is unnecessary.
• Automatic rotation based on orientation. The tool detects image orientation through EXIF metadata and can automatically rotate it for correct display (portrait/landscape) before resizing. This prevents incorrectly oriented images in the final output.
• Output file renaming. Allows defining a naming pattern for the resulting files, such as adding a suffix (_web, _resized) or a prefix while keeping the original name. It facilitates the identification of optimized versions compared to the originals.
• Output format selection. Although specialized in JPEG, the application can convert images from other input formats (PNG, BMP, TIFF) to the JPEG output format, unifying the file type for web environments where JPEG is the standard for photographs.
• ICC color profile handling. WebPrepImage preserves the color profile embedded in the original image during resizing, ensuring consistent color reproduction in browsers and devices that manage color.

The development history of WebPrepImage began in 2026. The program was created by the developer known as arbopa to solve a personal need when preparing images for upload to platforms with file size limits. Not finding a tool that combined longest-edge resizing with fine-grained file size control, he decided to program it. It is written primarily in the Python programming language, using libraries such as Pillow for image manipulation and tkinter for the graphical user interface.

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