diff --git a/src/components/common/ConversationTimeline.tsx b/src/components/common/ConversationTimeline.tsx
index e009f219..991de5f1 100644
--- a/src/components/common/ConversationTimeline.tsx
+++ b/src/components/common/ConversationTimeline.tsx
@@ -15,9 +15,41 @@ import rehypeRaw from 'rehype-raw';
 import { formatDate } from '../../utils/format';
 import { getGithubAvatarSrc } from '../../utils/ExplorerUtils';
 import { STATUS_COLORS, scrollbarSx } from '../../theme';
+import { isImageOnlyLinkChild, MarkdownImage } from './MarkdownImage';
 
 import 'github-markdown-css/github-markdown-dark.css';
 
+const conversationMarkdownComponents = {
+  img: (props: React.ImgHTMLAttributes<HTMLImageElement>) => (
+    <MarkdownImage {...props} />
+  ),
+  a: ({
+    href,
+    children,
+    ...props
+  }: React.AnchorHTMLAttributes<HTMLAnchorElement>) => {
+    if (isImageOnlyLinkChild(children)) {
+      const nodes = React.Children.toArray(children);
+      const only = nodes[0];
+      if (React.isValidElement(only) && only.type === MarkdownImage) {
+        return <>{children}</>;
+      }
+      if (React.isValidElement(only)) {
+        const imgProps =
+          only.props as React.ImgHTMLAttributes<HTMLImageElement>;
+        if (imgProps.src) {
+          return <MarkdownImage src={imgProps.src} alt={imgProps.alt} />;
+        }
+      }
+    }
+    return (
+      <a href={href} target="_blank" rel="noopener noreferrer" {...props}>
+        {children}
+      </a>
+    );
+  },
+};
+
 /** A comment or the body rendered in the conversation timeline. */
 export type ConversationItem = {
   id: string;
@@ -337,8 +369,11 @@ const ConversationTimeline: React.FC<ConversationTimelineProps> = ({
                   backgroundColor: colors.border.default,
                   border: 0,
                 },
-                '& img': {
+                '& .markdown-body img': {
                   maxWidth: '100%',
+                  width: 'auto',
+                  height: 'auto',
+                  objectFit: 'contain',
                   borderRadius: '6px',
                   backgroundColor: 'transparent',
                 },
@@ -348,6 +383,7 @@ const ConversationTimeline: React.FC<ConversationTimelineProps> = ({
                 <ReactMarkdown
                   remarkPlugins={[remarkGfm]}
                   rehypePlugins={[rehypeRaw]}
+                  components={conversationMarkdownComponents}
                 >
                   {item.body}
                 </ReactMarkdown>
diff --git a/src/components/common/ImageLightbox.tsx b/src/components/common/ImageLightbox.tsx
new file mode 100644
index 00000000..1aeddfb1
--- /dev/null
+++ b/src/components/common/ImageLightbox.tsx
@@ -0,0 +1,166 @@
+import React, { useCallback, useEffect } from 'react';
+import { Box, Fade, IconButton, Modal, Typography } from '@mui/material';
+import CloseIcon from '@mui/icons-material/Close';
+import OpenInNewIcon from '@mui/icons-material/OpenInNew';
+
+export interface ImageLightboxProps {
+  open: boolean;
+  src: string;
+  alt?: string;
+  onClose: () => void;
+}
+
+/**
+ * Full-screen image preview — opened when a markdown/issue screenshot is clicked.
+ */
+export const ImageLightbox: React.FC<ImageLightboxProps> = ({
+  open,
+  src,
+  alt,
+  onClose,
+}) => {
+  const handleKeyDown = useCallback(
+    (event: KeyboardEvent) => {
+      if (event.key === 'Escape') {
+        onClose();
+      }
+    },
+    [onClose],
+  );
+
+  useEffect(() => {
+    if (!open) {
+      return undefined;
+    }
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [open, handleKeyDown]);
+
+  return (
+    <Modal
+      open={open}
+      onClose={onClose}
+      closeAfterTransition
+      aria-labelledby="image-lightbox-title"
+      BackdropProps={{
+        sx: {
+          backgroundColor: 'rgba(0, 0, 0, 0.92)',
+          backdropFilter: 'blur(4px)',
+        },
+      }}
+      sx={{
+        display: 'flex',
+        alignItems: 'center',
+        justifyContent: 'center',
+        zIndex: (theme) => theme.zIndex.modal + 2,
+      }}
+    >
+      <Fade in={open}>
+        <Box
+          role="dialog"
+          aria-modal="true"
+          onClick={onClose}
+          sx={{
+            position: 'fixed',
+            inset: 0,
+            display: 'flex',
+            flexDirection: 'column',
+            alignItems: 'center',
+            justifyContent: 'center',
+            p: { xs: 2, sm: 3 },
+            outline: 'none',
+          }}
+        >
+          <Box
+            sx={{
+              position: 'absolute',
+              top: { xs: 12, sm: 20 },
+              right: { xs: 12, sm: 20 },
+              display: 'flex',
+              gap: 1,
+              zIndex: 1,
+            }}
+            onClick={(event) => event.stopPropagation()}
+          >
+            <IconButton
+              component="a"
+              href={src}
+              target="_blank"
+              rel="noopener noreferrer"
+              aria-label="Open image in new tab"
+              sx={{
+                color: 'common.white',
+                backgroundColor: 'rgba(255, 255, 255, 0.12)',
+                '&:hover': { backgroundColor: 'rgba(255, 255, 255, 0.22)' },
+              }}
+            >
+              <OpenInNewIcon />
+            </IconButton>
+            <IconButton
+              onClick={onClose}
+              aria-label="Close image preview"
+              sx={{
+                color: 'common.white',
+                backgroundColor: 'rgba(255, 255, 255, 0.12)',
+                '&:hover': { backgroundColor: 'rgba(255, 255, 255, 0.22)' },
+              }}
+            >
+              <CloseIcon />
+            </IconButton>
+          </Box>
+
+          <Box
+            onClick={(event) => event.stopPropagation()}
+            sx={{
+              display: 'flex',
+              flexDirection: 'column',
+              alignItems: 'center',
+              maxWidth: '100%',
+              maxHeight: '100%',
+            }}
+          >
+            <Box
+              component="img"
+              id="image-lightbox-title"
+              src={src}
+              alt={alt ?? 'Enlarged screenshot'}
+              sx={{
+                display: 'block',
+                maxWidth: 'min(96vw, 1600px)',
+                maxHeight: 'calc(92vh - 48px)',
+                width: 'auto',
+                height: 'auto',
+                objectFit: 'contain',
+                borderRadius: 1,
+                boxShadow: '0 24px 80px rgba(0, 0, 0, 0.55)',
+              }}
+            />
+            {alt ? (
+              <Typography
+                variant="body2"
+                sx={{
+                  mt: 1.5,
+                  color: 'rgba(255, 255, 255, 0.72)',
+                  textAlign: 'center',
+                  maxWidth: 'min(96vw, 720px)',
+                }}
+              >
+                {alt}
+              </Typography>
+            ) : (
+              <Typography
+                variant="caption"
+                sx={{
+                  mt: 1.5,
+                  color: 'rgba(255, 255, 255, 0.5)',
+                }}
+              >
+                Press Esc or click outside to close
+              </Typography>
+            )}
+          </Box>
+        </Box>
+      </Fade>
+    </Modal>
+  );
+};
diff --git a/src/components/common/MarkdownImage.tsx b/src/components/common/MarkdownImage.tsx
new file mode 100644
index 00000000..e75707c3
--- /dev/null
+++ b/src/components/common/MarkdownImage.tsx
@@ -0,0 +1,125 @@
+import React, { useState } from 'react';
+import { Box, Typography, alpha } from '@mui/material';
+import { ImageLightbox } from './ImageLightbox';
+
+type MarkdownImageProps = React.ImgHTMLAttributes<HTMLImageElement>;
+
+const openLightboxFromEvent = (
+  event: React.MouseEvent | React.KeyboardEvent,
+  open: () => void,
+) => {
+  event.preventDefault();
+  event.stopPropagation();
+  open();
+};
+
+/**
+ * Renders markdown/HTML images with preserved aspect ratio and a click-to-zoom lightbox.
+ */
+export const MarkdownImage: React.FC<MarkdownImageProps> = ({
+  src,
+  alt,
+  style: _inlineStyle,
+  width: _width,
+  height: _height,
+  onClick: _onClick,
+  ...rest
+}) => {
+  const [lightboxOpen, setLightboxOpen] = useState(false);
+
+  if (!src) {
+    return null;
+  }
+
+  const openLightbox = () => setLightboxOpen(true);
+
+  return (
+    <>
+      <Box
+        sx={{
+          display: 'inline-block',
+          maxWidth: '100%',
+          my: 2,
+        }}
+      >
+        <Box
+          component="button"
+          type="button"
+          onClick={(event) => openLightboxFromEvent(event, openLightbox)}
+          aria-label={alt ? `Enlarge image: ${alt}` : 'Enlarge image'}
+          sx={{
+            display: 'block',
+            p: 0,
+            m: 0,
+            border: 'none',
+            background: 'none',
+            cursor: 'zoom-in',
+            maxWidth: '100%',
+            borderRadius: '6px',
+            overflow: 'hidden',
+            '&:focus-visible': {
+              outline: '2px solid',
+              outlineColor: 'primary.main',
+              outlineOffset: 2,
+            },
+          }}
+        >
+          <Box
+            component="img"
+            src={src}
+            alt={alt ?? ''}
+            loading="lazy"
+            decoding="async"
+            draggable={false}
+            sx={{
+              display: 'block',
+              maxWidth: '100%',
+              width: 'auto',
+              height: 'auto',
+              objectFit: 'contain',
+              borderRadius: '6px',
+              backgroundColor: 'transparent',
+              pointerEvents: 'none',
+            }}
+            {...rest}
+          />
+        </Box>
+        <Typography
+          variant="caption"
+          sx={(theme) => ({
+            display: 'block',
+            mt: 0.5,
+            color: alpha(theme.palette.text.secondary, 0.85),
+            fontSize: '0.7rem',
+            letterSpacing: '0.02em',
+          })}
+        >
+          Click to enlarge
+        </Typography>
+      </Box>
+
+      <ImageLightbox
+        open={lightboxOpen}
+        src={src}
+        alt={alt}
+        onClose={() => setLightboxOpen(false)}
+      />
+    </>
+  );
+};
+
+/** GitHub often wraps screenshots in `<a><img /></a>` — unwrap so the lightbox receives clicks. */
+export const isImageOnlyLinkChild = (children: React.ReactNode): boolean => {
+  const nodes = React.Children.toArray(children);
+  if (nodes.length !== 1 || !React.isValidElement(nodes[0])) {
+    return false;
+  }
+  const child = nodes[0];
+  if (child.type === MarkdownImage) {
+    return true;
+  }
+  if (child.type === 'img' || (child.props as { src?: string }).src) {
+    return true;
+  }
+  return false;
+};
diff --git a/src/components/common/index.ts b/src/components/common/index.ts
index 81a26298..26e0aafd 100644
--- a/src/components/common/index.ts
+++ b/src/components/common/index.ts
@@ -5,3 +5,5 @@ export * from './WatchlistButton';
 export * from './DataTable';
 export { default as ConversationTimeline } from './ConversationTimeline';
 export * from './ConversationTimeline';
+export { MarkdownImage } from './MarkdownImage';
+export { ImageLightbox } from './ImageLightbox';