Zvětšení obrázku online

What Zvětšení obrázku does

Enlarging an image increases its pixel dimensions, for example to print a small photo, use a small logo in a larger layout or meet a minimum size required by a website.

The tool scales the image up in steps of at most 2× using the browser's high-quality smoothing, which fills the new pixels by blending their neighbors, and then applies optional light sharpening to make edges crisper. This is classic resampling, not AI upscaling: the image gets bigger and smoother, but detail that the original does not contain, such as hair or small text, is not invented.

Jak používat nástroj Zvětšení obrázku

1. Přetáhněte do pole jeden nebo více obrázků.
2. Nastavte možnosti nástroje „Zvětšení obrázku“ a zkontrolujte náhled.
3. Klikněte na Použít. Každý obrázek se zpracuje ve vašem prohlížeči.
4. Stáhněte upravené obrázky.

When to use Zvětšení obrázku

• Enlarge a small logo or icon to meet the minimum image size required by a marketplace, app store or website.
• Make an old low-resolution photo large enough to print at a bigger size with less visible blockiness.
• Upscale a small screenshot or graphic so it fills a presentation slide without looking pixelated.
• Prepare a small image for a design or print service that requires at least 1000 or 2000 pixels on each side.

Settings explained

Enlarge by

Multiplies the width and height by 1.5, 2, 3 or 4; 2× is the default. A 2× enlargement has four times as many pixels, so choose the smallest factor that gives the size you need.

Sharpen

On by default. Applies a light sharpening filter after enlarging to counter the softness that scaling causes. Turn it off for images with noise or JPG artifacts, because sharpening makes them more visible.

Output format

Same as input keeps the format, with HEIC saved as JPG and GIF or SVG saved as PNG. PNG suits logos and graphics, while JPG or WEBP keep large photos smaller.

Quality

Shown for JPG, WEBP and AVIF output and for Same as input. It ranges from 10 to 100 with a default of 85. Enlarged images are big, so 80 to 90 keeps files manageable.

Format comparison

Co je PNG?

PNG (Portable Network Graphics) je obrazový formát z roku 1996, jehož autorem je W3C. Formát používá bezeztrátovou kompresi a podporuje průhlednost. Soubory mají příponu .png.

PNG was created in the mid-1990s as a free replacement for GIF, whose compression method was covered by patents at the time. It applies a filtering step and then compresses pixels with the DEFLATE algorithm, so every pixel is kept exactly. It supports full color, grayscale, palette images and a full alpha channel for smooth transparency.

PNG is the right choice for screenshots, logos, icons, diagrams, user interface graphics and any image with sharp edges, text or flat colors. It is also a safe format for images that need transparent backgrounds or will be edited again.

Because PNG is lossless, photos saved as PNG are often several times larger than the same photo saved as JPG or WebP. PNG has no lossy mode, and a standard PNG file cannot store animation.

PNG opens in every modern web browser, on Windows, macOS, Linux, Android and iOS, and in practically all image viewers, image editors, office suites and design tools. It is one of the most widely supported image formats.

Co je JPG?

JPG (Joint Photographic Experts Group) je obrazový formát z roku 1992, jehož autorem je JPEG. Formát používá ztrátovou kompresi a nepodporuje průhlednost. Soubory mají příponu .jpg nebo .jpeg.

JPG, also written JPEG, is named after the Joint Photographic Experts Group, which wrote the standard. It splits an image into small blocks, transforms each block with a discrete cosine transform and discards the fine detail that the eye notices least. A quality setting controls how much detail is removed and therefore the file size.

JPG is the standard choice for photographs and other images with smooth color gradients, such as camera pictures, product photos and images for email or social media. It gives small files with good visual quality at moderate settings.

JPG does not support transparency or animation. Each time a JPG is edited and saved again, it loses a little more quality. Text, line art and sharp edges can show visible blocks or halos at low quality settings.

JPG is supported everywhere: in all web browsers, on all desktop and mobile operating systems, and on cameras, phones and printers. All image editors and office programs open it. It is the most compatible format for sharing photos.

Co je WEBP?

WEBP (WebP) je obrazový formát z roku 2010, jehož autorem je Google. Formát podporuje ztrátovou i bezeztrátovou kompresi, podporuje průhlednost a umí ukládat animace. Soubory mají příponu .webp.

WebP was developed by Google to make images on the web smaller. Its lossy mode is based on the VP8 video codec, and it also has a separate lossless mode. Both modes can include an alpha channel for transparency. The format also supports animation, so it can replace JPG, PNG and GIF in many cases.

WebP is a good choice for images on websites and in apps, where smaller files load faster. It works for photos, graphics with transparency and short animations, often at a smaller size than JPG, PNG or GIF.

Some older software, image editors, print services and upload forms still do not accept WebP. Lossy WebP always reduces color resolution, which can blur fine colored detail. At very high quality settings, the size benefit over JPG can be small.

All current major browsers display WebP, including Chrome, Edge, Firefox and Safari on recent versions of macOS and iOS. Windows, macOS, Android and most modern image editors open it, but some older desktop programs do not.

Co je AVIF?

AVIF (AV1 Image File Format) je obrazový formát z roku 2019, jehož autorem je Alliance for Open Media. Formát podporuje ztrátovou i bezeztrátovou kompresi, podporuje průhlednost a umí ukládat animace. Soubory mají příponu .avif.

AVIF stores images compressed with the AV1 video codec inside a HEIF-based container. It was developed by the Alliance for Open Media, a group that includes major browser and technology companies, as a royalty-free format. It supports high bit depth, wide color, HDR, transparency and image sequences.

AVIF is best for web images where file size matters most. It often produces smaller files than JPG or WebP at similar visual quality, especially for photos, and it is useful for HDR and wide color images.

Encoding AVIF is slow compared with JPG or WebP, especially at high quality settings. Many image editors, older devices and upload forms do not accept it yet. Fine detail and texture can look smoothed at low quality settings.

Current versions of Chrome, Edge, Firefox and Safari display AVIF. Recent Windows, macOS, iOS and Android versions can open it, sometimes with an extra codec extension, but support in editors, office software and older systems is incomplete.

Proč používat nástroj Zvětšení obrázku od FansBond

Většina online převodníků nahrává vaše soubory na své servery. Nástroj „Zvětšení obrázku“ od FansBond místo toho pracuje přímo ve vašem prohlížeči díky WebAssembly a moderním rozhraním prohlížeče. Soubory zůstávají ve vašem zařízení, což je bezpečnější pro soukromé fotky, smlouvy i nezveřejněnou práci, a často je to i rychlejší, protože se nic nemusí nahrávat ani stahovat.

Žádné fronty, žádné vodoznaky a žádný účet. Jakmile se stránka načte, nástroj funguje i na pomalém připojení.

Tips for the best result

• For SVG logos, set SVG render width to the final size instead of enlarging. Vectors are drawn sharply at any size.
• The result can have at most about 33 megapixels. For example, a 4000 × 3000 photo can be enlarged 1.5×, but not 2×.
• Start from the best source available. Enlarging a heavily compressed JPG also enlarges its blocks and color noise.
• Enlarge once by the factor you need instead of enlarging an already enlarged copy, which repeats the softening and sharpening.

How Zvětšení obrázku works in your browser

When you add an image, the browser decodes it into raw pixels on your device. HEIC photos are decoded with a browser build of libheif, and AVIF with the libavif decoder. The pixels are then processed on an HTML canvas and encoded again in the format you picked.

JPG, PNG and WebP are encoded with your browser's built-in encoders, and AVIF with libavif compiled to WebAssembly. The compressors add MozJPEG for smaller JPG files and OxiPNG for lossless PNG optimization. Because everything runs locally, the speed depends on your device rather than on a server queue.

Privacy and security

Most online converters upload your files to a server, process them there and keep a copy for some time. Zvětšení obrázku works differently: the code is downloaded to your browser once, and your files are read and written only on your device.

You can check this yourself: after the page has loaded, turn off your internet connection and the tool still works. This makes it safe for contracts, IDs, medical records, private photos and unreleased work.