How to batch convert a folder of JPGs to ICO
Convert JPG to ICO from a folder of JPG files, set the output to ICO with your size list, and run the batch. It writes one ICO per source image with the same size set, which online one-at-a-time tools cannot do.
Click Add Folder, point to the directory of JPG sources, set the output format to ICO, choose your target sizes, pick a destination, and click Start. The program creates one ICO per image with the same sizes. Batch mode is part of the paid license.

SoftOrbits Icon Maker Software helps you create icons from PNG images and other graphics for Windows, Android, and iOS.
nofollow">rebuilding the icon cache.
Is it safe to use an online JPG-to-ICO converter?
Online converters upload your image to a server you do not control, which is a real concern for personal photos or a company logo. A desktop tool converts on your PC, so the file never leaves the machine.
Browser converters can handle a single throwaway icon, but some free tools cap the quality, output a renamed PNG that fails in certain Windows contexts, or handle just one file at a time. For a company logo, a client's branding, or a folder of source art, a desktop icon maker clears the upload step and the per-file limit.
Why SoftOrbits JPG to ICO Converter Software fits JPG-to-ICO conversion
Icon Maker is a desktop converter and editor built for the icon job, with multi-size ICO output, an editor to clear the background for transparency, batch mode, and pixel tools for the small sizes.
Writes multi-size ICO files (16 x 16 through 256 x 256) in one pass
Editor clears a plain background and adds an alpha channel for transparency
Batch-converts a directory of images in one run
Built-in pixel editor to fix the 16 x 16 version by hand
Opens JPG, PNG, BMP, GIF and TIFF sources; the icon itself saves as ICO, with ICL for libraries and CUR for cursors when you need them
It is a Windows desktop app, not a browser tool
Batch mode and watermark-free output need the paid license
When you need an offline, repeatable way to convert JPG to ICO with clean transparency, use desktop icon maker software like Icon Maker. The trial covers the full workflow and adds a watermark to the output. A one-time license removes the watermark and turns on batch processing. See pricing on the product page.