Does making an image smaller reduce its quality?

Shrinking discards information, so you won’t notice any degradation when viewing it at the reduced size. Quality drops when you enlarge. When shrinking a lot, this tool scales down by half at a time in steps, which reduces the jagged edges that appear when shrinking all at once. However, exporting as JPEG or WebP adds separate compression loss, so for assets you’ll edit later, keep the quality high or export as PNG.

How many pixels should a social media icon be?

An 800×800 px square is enough for most services. Many services recommend around 400×400 px, and uploading a larger image just gets it scaled down without degradation. A smaller image, on the other hand, gets enlarged and looks blurry. Many services crop icons into a circle, so overlay the “circle mask and center 70% safe area” on the result preview to check that faces and logos fit inside the circle.

What size is a link card (OGP) image?

1200×630 px (about 1.91:1) is the standard. Press the “Link card (OGP)” preset to export the image cropped to this size. Since the cropped area differs depending on where it’s displayed, it’s safest to keep text and logos inside a margin of 60–70 px on all sides. Aim for 1 MB or less, and if it’s larger, export as JPEG with the quality lowered to 80–90%.

How many pixels do I need to print at A4 size?

At 300 dpi, 2480×3508 px; at 350 dpi, about 2894×4093 px. The formula is “finished length (mm) ÷ 25.4 × dpi”, and since A4 is 210×297 mm, 210 ÷ 25.4 × 350 = about 2894. Choose the paper and dpi on the “Print size” tab to see the required pixels and whether your image has enough. If it doesn’t, it also shows the maximum dpi that image can achieve.

Can I print it if I just change the dpi value to 350?

That’s fine as long as the original has enough pixels, because dpi is a print setting, not the amount of information the image actually holds. If there aren’t enough pixels, raising the dpi won’t make it sharper. First use the “Print size” tab to calculate the required pixels from the finished size and compare them with your image. For things viewed from a distance like posters, 150–200 dpi is practical, and for banners even 50–100 dpi works.

Can I change only the size without changing the aspect ratio?

Yes. Under “Width and height”, check “Keep original ratio”, and entering one side automatically sets the other. The ratio is also kept when you specify by “Long side” or “Scale”. The crop, fit, or stretch options only appear when you specify a size with a different ratio.

Are uploaded images stored?

No upload happens at all. Loading, resizing, and exporting images all take place in your browser, and nothing is sent to a server. You can safely use unpublished materials or personal photos. When you close the page, the loaded image is discarded too.

Image Resizer (with Aspect Ratio and Print Size Calculators)

Drop an image and set the width and height, the long side, or a scale, and it’s resized and exported right in your browser. It includes presets for common uses such as an 800×800 social media icon or a 1200×630 link card, shows what gets cropped when an image goes into a frame with a different ratio, and calculates the pixels you need from the paper size and dpi you want to print at.

ABOUT

About Image Resizer (with Aspect Ratio and Print Size Calculators)

The image resizer changes the width and height of an image in pixels and exports it. You can set the size by width and height, the long side, or a scale, and pick purpose-based presets such as an 800×800 social media icon or a 1200×630 link card. When fitting an image into a frame with a different ratio, choose from three options: crop, fit with padding, or stretch. Even without loading an image, you can use just the aspect ratio calculator and the print pixel calculator.

How to use Image Resizer (with Aspect Ratio and Print Size Calculators)

1Drop an image onto the “Resize” tab (or click to choose a file)
2Press a preset for your purpose, or set the output size by width and height, long side, or scale
3If the ratio differs from the original, choose crop, fit, or stretch (for cropping, you can also choose which part to keep)
4Choose the output format (same as original, PNG, JPEG, or WebP) and, for JPEG or WebP, the quality
5Press “Resize”, check the output size and file size, then download
6If the image is going to print, choose the paper and dpi on the “Print size” tab to check that you have enough pixels

Great for

Shrink a 4000×3000 photo taken on your phone to fit within an upload limit
Crop a photo to a square (800×800 px) for a social media icon
Fit an image to the 1200×630 px OGP size for a blog link card
Size an image to 1280×720 px for a video thumbnail
Check whether an image you have has enough pixels to print an A4 flyer at 350 dpi
Before starting a design, decide how many pixels to create (2×) from the display width

Good to know

Resizing is done directly from the original image. When shrinking a lot, it scales down in steps rather than all at once, so jagged edges are less likely.
A warning appears if you specify a size larger than the original. Enlarging pads out pixels that weren’t there, so the result will always be softer.
When fitting into a frame with a different ratio, you can choose crop (edges are cut off), fit (padding is added), or stretch (the image is distorted). For cropping, you can choose which part to keep from 9 positions such as center, top, and top left.
JPEG can’t handle transparency, so padding and transparent areas are filled with white. Choose PNG or WebP to keep transparency.
Even if you choose “Same as original” for the output format, formats the browser can’t export, such as HEIC or GIF, become PNG.
The print size formula is “finished length (mm) ÷ 25.4 × dpi”. To print A4 (210×297 mm) at 350 dpi, you need about 2894×4093 px.
For borderless (full-bleed) printing, calculate with 3 mm of bleed added on each side (you can switch this with a single checkbox).
Resizing and calculations all happen in your browser, and images are never sent to a server. The share URL contains only the width and height in pixels.

Questions this tool answers

Use Image Resizer (with Aspect Ratio and Print Size Calculators) for searches like these:

I want to make an image smaller
I want to crop a photo into a square for an icon
I want to fit this image to the 1200×630 px OGP size
I want to resize by specifying only the width while keeping the aspect ratio
I want to know how many pixels I need to print A4 at 350 dpi
I want to check whether my photo is good enough to print

FAQ

Does making an image smaller reduce its quality?: Shrinking discards information, so you won’t notice any degradation when viewing it at the reduced size. Quality drops when you enlarge. When shrinking a lot, this tool scales down by half at a time in steps, which reduces the jagged edges that appear when shrinking all at once. However, exporting as JPEG or WebP adds separate compression loss, so for assets you’ll edit later, keep the quality high or export as PNG.
How many pixels should a social media icon be?: An 800×800 px square is enough for most services. Many services recommend around 400×400 px, and uploading a larger image just gets it scaled down without degradation. A smaller image, on the other hand, gets enlarged and looks blurry. Many services crop icons into a circle, so overlay the “circle mask and center 70% safe area” on the result preview to check that faces and logos fit inside the circle.
What size is a link card (OGP) image?: 1200×630 px (about 1.91:1) is the standard. Press the “Link card (OGP)” preset to export the image cropped to this size. Since the cropped area differs depending on where it’s displayed, it’s safest to keep text and logos inside a margin of 60–70 px on all sides. Aim for 1 MB or less, and if it’s larger, export as JPEG with the quality lowered to 80–90%.
How many pixels do I need to print at A4 size?: At 300 dpi, 2480×3508 px; at 350 dpi, about 2894×4093 px. The formula is “finished length (mm) ÷ 25.4 × dpi”, and since A4 is 210×297 mm, 210 ÷ 25.4 × 350 = about 2894. Choose the paper and dpi on the “Print size” tab to see the required pixels and whether your image has enough. If it doesn’t, it also shows the maximum dpi that image can achieve.
Can I print it if I just change the dpi value to 350?: That’s fine as long as the original has enough pixels, because dpi is a print setting, not the amount of information the image actually holds. If there aren’t enough pixels, raising the dpi won’t make it sharper. First use the “Print size” tab to calculate the required pixels from the finished size and compare them with your image. For things viewed from a distance like posters, 150–200 dpi is practical, and for banners even 50–100 dpi works.
Can I change only the size without changing the aspect ratio?: Yes. Under “Width and height”, check “Keep original ratio”, and entering one side automatically sets the other. The ratio is also kept when you specify by “Long side” or “Scale”. The crop, fit, or stretch options only appear when you specify a size with a different ratio.
Are uploaded images stored?: No upload happens at all. Loading, resizing, and exporting images all take place in your browser, and nothing is sent to a server. You can safely use unpublished materials or personal photos. When you close the page, the loaded image is discarded too.

Special Thanks

SOLO GUILD | サービス作るAIエンジニア

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