XnConvert is a fast, powerful and free cross-platform batch image converter, It allows to automate editing for your massive photo collections, you can rotate, convert and compress your different images, photos and pictures easily, and apply over 80 actions (like resize, crop, color adjustements, filter, …). All common picture and graphics formats are supported (JPEG, TIFF, PNG, GIF, WEBP, PSD, JPEG2000, OpenEXR, camera RAW, HEIC, PDF, DNG, CR2).