Web Image Optimizer

What it does

A photo straight off a modern phone might be 4,000 pixels wide and several megabytes in size. A website usually only ever displays it at around 1,200 pixels. The visitor's browser still has to download the whole thing, so pages feel slow, and slowest of all for someone on mobile data.

Web Image Optimizer does the boring part of fixing that, in bulk:

• Works on a whole folder at once, and can include subfolders if you want it to.
• Resizes down to a maximum width you pick (800 up to 4096 pixels, 1920 by default). If a photo is already smaller than that, it is left at its own size. It never stretches a small picture to make it bigger.
• Compresses at a quality level you choose from 1 to 100, with 85 as a sensible starting point.
• Saves as JPEG, PNG, WebP or AVIF, whichever suits your site.
• Renames in a tidy sequence, so you can turn IMG_4471.HEIC into kitchen-01.jpg, kitchen-02.jpg and so on. You set the base name and the starting number.
• Lets you check first. You can reorder the list, look at a thumbnail of each photo, and preview the output filenames before anything is written.
• Opens the awkward formats as well as the obvious ones: JPG, PNG, TIFF, WebP, BMP, GIF, AVIF, and the HEIC files that iPhones produce.
• Keeps a running log so you can see exactly what it did to each file.

The optional TinyPNG setting

There is a setting to use the TinyPNG (Tinify) service for compression instead of doing it on your own machine. It is off by default and it needs your own free API key from TinyPNG. Leave it alone and the app never touches the internet: all the work happens locally on your computer. If you do turn it on, your images are sent to TinyPNG for compression, so only use it if you are happy with that.

What it does not do

I would rather be straight with you about the limits than have you download it and be disappointed.

• It is not a photo editor. There is no cropping, straightening, colour correction or retouching.
• The copies it makes are compressed, which loses a little detail. That is the whole point of the tool, but it means the copies are for the web, not for archiving or printing. Keep your originals.
• The copies do not carry the original photo's EXIF data (camera model, date taken, GPS location). For a public website that is usually exactly what you want, but if you need that information preserved, this is the wrong tool.
• If a picture with a transparent background is saved as a JPEG, the transparency is filled in with white, because JPEG cannot store it. Save as PNG, WebP or AVIF if you need to keep it.
• It is Windows only. There is no Mac or Linux version.

Who it is for

I wrote this for the situation I keep running into with clients: someone has a website, they have added photos straight from their phone, and now their pages take an age to load. They do not want to learn Photoshop to fix it. They just want the pictures to be a sensible size.

It will probably suit you if:

• You run a small business, shop or portfolio site and upload your own photos.
• You have a folder of phone pictures that need consistent names and sensible dimensions before they go anywhere near a web page.
• You are doing this to dozens or hundreds of images, and doing them one at a time is not realistic.

It is probably not for you if:

• You only need to shrink one or two pictures. The Photos app already built into Windows will do that in less time than this takes to download.
• You are a photographer who needs the original quality, the full resolution or the EXIF data kept intact.
• You need editing rather than resizing.
• You are on a Mac.

Before you use it

The app writes its copies into a destination folder that you choose. As long as that is a different folder from the one holding your originals, your originals are not touched. If you do point the output at the same folder, the app warns you before it writes anything. Even so, please take the usual sensible precautions. They cost you two minutes and they protect you against my mistakes as well as your own.

• Choose a destination folder that is not your source folder, and preferably an empty one. That keeps the new copies clearly separated from the originals.
• Close the photos in anything else first, such as an editor or a preview window, so nothing has a lock on the files.
• Try a handful before you do the lot. Run five or six photos through, look at the results at full size, and check you are happy with the quality setting before you point it at 500 images.
• Read the overwrite prompt. If files with the same names already exist in the destination, the app stops and asks whether to overwrite them all or skip them all. Take a second over that question, because overwriting cannot be undone.

Safety and trust

This app is completely free. There are no adverts, no upsells, no account to create, no nag screens, and nothing that phones home. It does not send your images anywhere and it does not collect anything about you. The only exception is the optional TinyPNG setting described above, which is off unless you deliberately switch it on with your own key.

Please scan the download with your own antivirus if you would like extra reassurance. I would rather you checked than simply took my word for it. Your antivirus is already on your machine and it costs you nothing to use it. If you would like a SHA256 checksum of the file so you can verify it has not been altered in transit, ask me and I will publish one here.

Disclaimer

I give this away for nothing, so it does not come with a support service. I cannot promise to answer questions about it, fix problems with it, or keep updating it. If you need a tool that is properly supported and built for your situation, that is the paid work below.