Why do my images load so slowly or not at all on mobile?

You open your site on your phone, you wait, and the photo of your product shows up late, loads piece by piece, or worse, stays a blank square. On your laptop everything looks fine, but your customer is on mobile, often on cellular data, out on the street or in a waiting room.

The good news: the problem almost always has a concrete cause and, in most cases, is fixable without rebuilding the site. Here I explain the four real reasons images load slowly or not at all on mobile, and how to check each one yourself, even if you're not technical. At the end I tell you what to do next.

The main reason: the photos are far too heavy as files

The most common cause has nothing to do with the phone and everything to do with the photo. A modern camera or phone produces images of several megabytes each. If you upload the photo straight to the site, exactly as it came off the phone, the mobile browser has to download that whole huge file over a connection that's often much slower than home wi-fi.

How to check: save the photo from the site to your computer and look at the size. If a single image is over one megabyte, it's too big for the web.

What it should be: a photo properly prepared for the web is generally under a few hundred kilobytes, in a modern format (WebP or AVIF), resized to the actual width it's displayed at. It looks identical, but loads almost instantly.

The "broken" image: wrong link or moved file

When you see a blank square, a broken-image icon or just some text in place of the picture, it isn't a speed problem, it's a dead link. The photo exists in the code, but not at the address the page is looking for.

Typical causes:

• The file was deleted, renamed or moved to another folder after publishing.
• The photo was hosted on another site or an account that no longer exists.
• The address has capital letters or spaces written differently from the real file (servers treat Photo.JPG and photo.jpg as different).

A useful tell: if the photo is missing on both phone and laptop, it's almost certainly a broken link, not speed. If it shows on the laptop but is missing on mobile, the cause is usually something else, covered below.

Lazy-load: images that only load when you reach them

Modern sites use a technique called lazy-load: images further down the page don't download right away, only when you scroll toward them. Done right, it saves data and speeds up the first view.

The trouble comes when it's badly configured. On mobile, where you scroll quickly with your thumb, the photo doesn't get a chance to load before you see it, so it stays blank for a second or two, then pops in suddenly. Sometimes an aggressively applied optimization plugin causes exactly this annoying effect, especially on slow connections.

How to recognize it: on a laptop with good internet everything is smooth, but on the phone photos appear with a "jump" as you scroll. The fix isn't to switch lazy-load off entirely, but to let the important top image (the first one the customer sees) load immediately, and the rest load progressively.

How to check it yourself, in a few minutes

You don't need complicated software to work out what's happening:

• Open the site on your phone, but on cellular data, not wi-fi. That's what the real customer sees.
• Save a few photos and check the file size. Over one megabyte per image is a clear signal.
• Compare: is the photo missing on the laptop too? Then it's a broken link. Does it show on the laptop but lag on mobile? Then it's size or lazy-load.
• Test the page with a free speed tool (Google's PageSpeed Insights). It tells you directly whether the images are too big or in an old format.

These four checks usually show you exactly which of the three categories you fall into, without guessing.

What to do next

If it's just a few photos, you can resize and compress them yourself with a free tool, then re-upload them. If the whole site is full of heavy images or you see blank squares everywhere, it's more than an evening chore and worth doing properly.

That's how we work at MPO Web Studio: we prepare images in a modern format, at the right sizes for mobile, and configure lazy-load so the first photo appears instantly while the rest flow in smoothly. We work remotely, across the whole country, with prices stated clearly up front, and for new clients we first build a free demo version so you can see the result before you decide.

If you like, send us a WhatsApp message with your site's address and we'll tell you honestly which of the three problems you have and how long it would take to fix.