JPG to PDF Converter

About JPG

JPEG (Joint Photographic Experts Group) is the most widely used image format in the world. Standardised in 1992, it remains the default for digital photography, web images, and email attachments because it achieves the optimal balance between file size and visual quality for photographic content. A 12-megapixel camera photo that occupies 36 MB as a raw file typically compresses to 3–5 MB as a JPEG at high quality — a 7–12× reduction with no visible difference on screen.

JPEG uses lossy compression based on the Discrete Cosine Transform (DCT). The algorithm divides the image into 8×8 pixel blocks, converts each to frequency components, and discards the high-frequency detail that human vision is least sensitive to. At quality settings between 75–90%, the result is visually indistinguishable from the original. At lower quality settings (below 60%), you start to see blocky artifacts in smooth areas — a characteristic called "ringing" or "mosquito noise" near sharp edges.

When JPEG is the right choice

JPEG is the right format for photographs, portraits, landscapes, and any image with complex color gradients and natural scenes. Its universal support — every browser, every operating system, every email client, every image editing application — means a JPEG will open anywhere without additional software or codec downloads. For distribution to a wide audience or archiving in a format guaranteed to remain readable for decades, JPEG is the safe universal choice.

When JPEG is the wrong choice

JPEG does not support transparency (alpha channel). For logos, icons, screenshots with transparent backgrounds, or UI graphics that need to sit cleanly over any background color, PNG or WEBP is necessary. JPEG also re-compresses every time you save at a lossy quality level, so re-saving an already-compressed JPEG introduces cumulative quality loss — always keep original source files in a lossless format and convert only for final output.

JPEG vs. modern formats

WEBP, AVIF, and HEIC all achieve smaller file sizes than JPEG at equivalent visual quality. WEBP produces files 25–35% smaller than JPEG and is now supported by all major browsers. AVIF achieves 40–50% smaller files and is supported in Chrome 85+, Firefox 93+, and Safari 16+. For new web image assets, these formats are better choices when file size matters. JPEG remains the right choice when maximum device and software compatibility is the priority, or when images will be used in workflows that do not yet support newer formats.

About PDF

PDF (Portable Document Format) was created by Adobe in 1993 and standardised as ISO 32000 in 2008. It is the universal container for documents that must look identical on every device — fonts, layouts, vector graphics, embedded images, and hyperlinks all render consistently regardless of the operating system, application, or screen resolution.

When converting a PDF page to an image format (JPG, PNG, WEBP, or AVIF), the PDF is rasterised: each page is rendered as a grid of pixels at a specified DPI (dots per inch) resolution. This site uses ImageMagick with a Ghostscript backend for PDF rasterisation. At 150 DPI, an A4 page renders to approximately 1240 × 1754 pixels — sufficient for most presentation, social media, and documentation use cases. For print-quality output, higher DPI values produce proportionally larger pixel dimensions.

Transparency in PDFs is handled differently depending on the output format. JPEG has no alpha channel, so transparent areas are composited against a white background before encoding. PNG and WEBP retain the alpha channel, so transparent page regions produce transparent pixels in the output. Only the first page is extracted per conversion — for multi-page extraction, split the PDF first.