Guides
Answers to the upload problems people actually hit, each one linked to the free tool that fixes it.
File Size 7
- Compress an image to 20KB20KB is an aggressive limit that only works for small images. What dimensions fit, why PNG often fails, and when the real problem is a minimum size.
- Compress an image to 50KBGet an image under 50KB by setting the pixel size first and the quality second. Why a phone photo can't just be squeezed, with the arithmetic.
- Compress an image to 100KBA 100KB limit is a balancing act between pixel size and JPEG quality. How to choose the dimensions that leave room for good quality.
- Compress an image to 200KB200KB usually lets you keep full-size dimensions. How to hit it without shrinking the picture, plus the Safari encoder difference we measured.
- Reduce image size without quality lossYou can't shrink a photo for free, but you can lose far less than a blind slider does. Pixels, quality and format explained, and what the numbers mean.
- Image too large to uploadWork out which kind of 'too large' you have (file size, pixel dimensions or both) and which setting fixes it, with the tool for each.
- Why is my image file so large?A phone photo is millions of pixels. How file size is made up, why PNGs and screenshots balloon, and what actually makes a picture smaller.
Image Dimensions 3
- Resize an image to exact pixelsSet an exact width and height (200 × 230, 600 × 600 or any size) without distorting the picture: crop to fit, fit inside, or stretch, and what each costs.
- Resize an image without stretchingKeep the shape right when you change an image's size: the aspect ratio formula, when to crop, when to pad, and a worked example from 4:3 to square.
- Image dimensions vs file sizeDimensions count pixels; file size counts bytes. How they relate, why the same dimensions can give very different file sizes, and which tool to use.
DPI & Quality 3
- Change an image to 300 DPISet the DPI a form asks for by editing the file's resolution tag. Which formats can take it, what doesn't change, and how to verify the result.
- 72 DPI vs 300 DPIGoing from 72 to 300 DPI changes the print size the file claims, not the pixels or how it looks on screen. A table of print sizes, and when the number matters.
- DPI vs pixel dimensionsPixels are the real size of an image; DPI is a label that relates pixels to print size. The formula, a conversion table, and a real notice whose numbers disagree.
PDFs 6
- Compress a PDF under 500KBWhether a PDF fits under 500KB depends on what is inside it. Real results on nine public PDFs, and what to do when the target can't be reached.
- Compress a PDF under 1MBUnder 1MB is reachable for many scans. How the compression modes differ, how to work out a per-page budget, and which mode got real PDFs there.
- PDF too large to uploadFind out what is making your PDF big (scans, photos or page size), then shrink it without breaking it, and what to try when compression isn't enough.
- Reduce a scanned PDF's sizeWhy scanned PDFs are huge, what resolution and colour to scan at, and what happens to a scan when it is compressed, with real before and after sizes.
- Compress a PDF without blurry textReal text stays sharp when a PDF is compressed; scanned text is a picture and can soften. How to tell which you have, and how to keep it readable.
- Are online PDF compressors safe?It depends on whether the tool uploads your file or processes it in your browser. How to tell the difference, and what local processing does and doesn't protect.
Applications & Signatures 6
- Resize a signature for an online formTurn a phone photo of your signature into a clean image that fits a form's size and KB limits, without stretching it or losing the strokes.
- Reduce a signature file size in KBSignature images are small and plain, so the usual problem is the opposite: too light for a minimum. How to hit both a maximum and a minimum KB.
- Clean a signature's backgroundTurn a phone photo of a signature into dark ink on white (or transparent PNG): what the tool does, what it can't, and how to photograph it for the best result.
- Resize a thumb impressionPhotograph a thumb print so it stays clear, then fit it to a form's pixel size, DPI and KB range without inventing or redrawing any detail.
- Resize a handwritten declarationPhotograph a handwritten declaration so it's readable, then fit it to the form's size, DPI and KB range. Layout tips for wide, short frames.
- Prepare an application photoTake, crop and fit a photo to a form's pixel size, KB range and format. What the tool handles, what only you can judge, and a conversion from mm to pixels.
Upload Problems 6
- Why won't my image upload?A checklist of the reasons an image upload fails (size, dimensions, format, DPI, damaged files) with how to test each and which tool fixes it.
- Fix "file size exceeds maximum limit"What the file-size error means, how to read the limit correctly (KB, MB, 1000 vs 1024), and how to get an image or PDF under it.
- Fix an "invalid image dimensions" errorThe kinds of dimension rules (exact, minimum, maximum, aspect ratio), how to read yours, and how to resize or crop to meet them without distortion.
- Fix an unsupported format errorWhich image formats websites refuse (HEIC, WebP, AVIF), why renaming a file doesn't work, and how to convert to the format the site wants.
- Check a file against upload requirementsTest an image against a site's rules before you submit: format, dimensions, file size and DPI, with required, preferred and 'check yourself' rules kept apart.
- Fix a file to match upload requirementsPaste the requirements and WillItUpload fixes format, dimensions, size and DPI together, then re-reads the file to confirm. How it works, and where it stops.
File Formats 1
Privacy & Security 1
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