Adding an image to an existing PDF — a logo, a photo, a stamp, a diagram — is an overlay operation. The image gets placed as a new element on top of the existing page content. You can position it anywhere on the page and resize it, but it doesn't push existing content out of the way the way it would in a Word document.
Browser-Based Tool: Quickest Path
WukongPDF's PDF Editor lets you upload a PDF and insert an image directly in the browser — no software needed. Click the image insertion tool, select your image file (JPG, PNG, SVG), and it appears on the page. Drag to position it, drag the corner handles to resize, and download the result. The image is embedded in the PDF as a new content element, not as an annotation, so it appears in every viewer and prints correctly.
One practical use case: adding a company logo to a PDF that was created without one, or adding a signature image to a document before sending. Both of these work well with a browser tool — the image placement is straightforward and the output is a clean PDF with the image embedded.
On Mac: Preview With the Markup Toolbar
Preview can insert images through the Markup toolbar. Open the PDF in Preview, open the Markup toolbar (pen-tip icon), then go to Tools → Annotate → Signature → Manage Signatures for signature images, or drag and drop an image file directly from Finder onto the open PDF page. Preview places it as a movable, resizable element. Once positioned, File → Export as PDF saves the result with the image embedded.
Dragging and dropping works for PNG and JPG files. The image arrives wherever you dropped it and can be repositioned by dragging, resized by pulling corner handles. It sits as an annotation layer rather than being embedded directly in the page content, which means most PDF viewers display it correctly but it behaves slightly differently from images added directly to the page structure.
Adobe Acrobat Pro: Editing the Page Content Directly
For more precise image insertion — particularly when you need the image to be part of the base page content rather than an overlay layer — Acrobat Pro's Edit PDF tool is the more capable option. Go to Tools → Edit PDF → Add Image, select the image file, and place it on the page. Acrobat embeds the image directly in the page content stream rather than as a floating annotation, which means it behaves consistently in all contexts including print production workflows that flatten annotations.
Acrobat also gives you more control over image properties — you can set the compression level for the inserted image, control its blending with underlying content, and ensure it's properly embedded for archival formats like PDF/A.
Image Quality and File Size After Insertion
When you insert a large, high-resolution image into a PDF, the file size increases accordingly. A 5MB PNG inserted into a 500KB document produces a noticeably larger file. If file size matters, resize the image to approximately the display size you need before inserting — there's no benefit to embedding a 4000-pixel-wide image if it's only going to appear at 300 pixels wide in the document.
After inserting images, running the PDF through a PDF Compression tool reduces the overall file size by optimizing the embedded image data. This is particularly useful when inserting multiple images or when the source images were high-resolution photographs that haven't been pre-optimized for document use.