Improve image loading with modern formats and right sizing

Images are usually the heaviest part of a page, so shrinking them has a dramatic impact on load time. The two biggest wins are modern formats and right sizing: serve modern image formats instead of old JPEG/PNG, and send each device images in resolutions it needs. That means mobile gets a mobile-resolution image — not a scaled down desktop-sized file. Do this consistently and pages feel faster without any loss in quality.

The purpose of modern image formats is obvious — to deliver the same visual quality with fewer bytes. The leading formats in modern web are AVIF and WebP. AVIF usually gives the smallest files for photos and gradients, while WebP is a widely supported workhorse that’s smaller than JPEG/PNG and supports transparency. Great news is that majority of cloud hosting platforms support image format conversion at the level of deployment pipeline. With these, any image that your team adds on the website will be automatically converted to modern format and optimized.

Another important thing to mention — always stick to vector format for graphics. Logos, icons, and any custom shape should be drawn in SVG, or styled with CSS. Vector images are significantly smaller in sizes compared to raster images.

Right image sizing means each device (e.g. a laptop or mobile phone) downloads only as many pixels as it can actually show. You should create a few size variants for key breakpoints of each image so phones get small files and large screens get larger ones. High-density ('Retina') screens should get sharper versions without forcing everyone else to download extra bytes.

Modern tools can handle most of this automatically: you upload a good source image, and the system serves the best-fit size for the user’s screen. However you should add simple guardrails — cap the maximum dimensions, and set clear aspect ratios, so you never send a desktop-sized image to a phone. Rendering of different images for different aspect ratios is also done automatically, modern web developed enough support for this functionality.

Prioritize images that are visible and delay the ones that aren’t. Bandwidth is limited, so deferring off-screen images lets the first screen load faster and brings a meaningful view sooner. Use lightweight placeholders (a solid dominant color or a soft blur) so image areas don’t look empty while the real file arrives. Avoid spinners — they add motion without reducing wait time. If the hero image is the main element on the page, don’t lazy-load it — load it eagerly.

Don’t overdo lazy-loading. Galleries, carousels, and long pages benefit from it, but aggressive delays on near-viewport images can cause a 'pop-in' effect. Test the first scroll on your key templates and keep the experience smooth.

Use a content delivery network (CDN) for images. A CDN is a mesh of servers around the world that stores copies of your files closer to visitors of your website. Shorter distance means quicker downloads and fewer slowdowns during traffic spikes. It also takes load off your main server, so the site stays stable when campaigns hit. Nearly all modern hosting platforms and site stacks include a CDN or plug into one. The main differences are price and control (how much storage, how aggressive caching can be, image resizing features). Pick the simplest option your platform offers first; you can always tune policies later as traffic grows.

It should be clear that modern formats, right sizes, and a bit of automation bring significant speed gains. To get quick results start with AVIF/WebP, and responsive sizing. As more advanced steps add CDN rules for caching and CI/CD automation, and keep an eye on the metrics. This way your website will stay fast as it grows.