XnConvert

XnConvert is a fast, powerful and free tool that can convert multiple images at once. It supports many common graphic formats like JPEG, TIFF, PNG, GIF, WebP, PSD, JPEG2000, JPEG-XL, OpenEXR, AVIF, HEIC, HEIF and PDF. Also several RAW image formats like Camera RAW, ORF, CR2 and DNG can be converted. Also many parameters can be adjusted before batch converting the images. It allows you to automate editing of your photo collections: you can rotate, convert and compress your images, photos and pictures easily, and apply over 80 actions (like resize, crop, color adjustments, filter, ...).